Gcc Include Path

Install GCC, GFortran, and GNU Make on Windows via MinGW 19 September, 2019. If you dont want the system includes like. Specifying Path Names for Include Files. Note that if you supply a valid compile_commands. out out will contain machine code for all the functions defined in test. A typical compilation command for a source file example. 0: Sets the unformatted single argument string to be passed to the compiler if fork is set to true. In the resulting project template, Visual Studio retains the intellisense and code completion feature,. MinGW is a native Windows port of the GNU Compiler Collection (GCC), with freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. Of course you can do all your development for CS444 by remote login to our Solaris UNIX servers, notably ulab. d dependency files for you, which are mini makefile fragments containing the dependencies of the. It includes the GNU Compiler (GCC) and is available free of charge directly from Arm for embedded software development on Windows, Linux and Mac OS X operating systems. The following report describes how gcc/g++ 4. The name "LLVM" itself is not an acronym; it is the full name of the project. Automatically add project directory to flycheck clang/gcc include path. You can specify a file name either by using a full path name or by using a relative path name. 'fopen' are not defined although I did include or (I tried both of them, they both don't work). NetBeans C/C++ pack has been tested with the following compilers and tools: Sun Studio 12 C compiler, Red Hat Fedora Core 3 gcc, and Ubuntu 6. gcc -M test. What should I append to my. Project Explorer DID display the paths under Includes. gcc -l links with a library file. a file or specifying a library by name, for example: -lfftw3 to link with libfftw3. Specifically: no include path added. h header file in your code. If you search the internet, you will find many sites on how to build the avr-gcc toolchain, most of which are very much dated. -I, --include-directory , --include-directory=¶ Add directory to include search path-I-, --include-barrier¶Restrict all prior -I flags to double-quoted inclusion and remove current directory from include path. This is the path to the GCC linker command file specific for the MSP430F5438A. 18 kernel, than i've. There is no library to link to. PREFIX overrides the installation path and should usually be set to /usr. To solve this problem, the GCC back-end may provide a secondary OS multilib suffix which is used in place of the primary multilib suffix for all library directories derived from *system* paths as opposed to GCC paths. Stack Exchange Network. 3 as the default C and C++ compiler. bashrc 파일 마지막 부분에 아래 커맨드를 추가한다. The default location of the gsl directory is /usr/local/include/gsl. This Mini-HOWTO further develops the theme introduced by the IncludePathHOWTO, progressing to a complementary consideration of where the MinGW implementation of GCC, (or more accurately, of the linker, ld, which is actually a component of the GNU binutils package), searches for object code libraries. 0 environment and unzipped it. g++ include path It's not that I want tothe code is not written by me originally. /include -I/usr/local/include helloworld. Show comments 2. Since I don't have root access on this machine, and so I have appended to a lot of those variables. Fast execution. For example, when I have:. GCC will list the defaults by running " arm-none-eabi-gcc -xc -E -v -" , and add those paths as well. Go to Cross GCC Linker->Libraries, and under Library search path (-L), add the path to \ccs_base\msp430\include_gcc. In my opinion, the reason it fails, is that it exceeds the maximum path size for relative paths, in WIndows (the large string above, has 250 characters, and i think that when GCC tries to append yet another file name, it exceeds the 260 characters). Libraries in UNIX. If a -rpath option is used, the runtime search path will be formed exclusively using the -rpath options, ignoring the -L options. Domestic inflation—albeit low—has differed across countries, leading to diverging paths for real effective exchange rates. Most probably you are running on Windows, and forgot to add the builder tools or to add the path to them. csv in its include path on the latest version of GCC: [[email protected] ~]$ msp430-elf-gcc -o main. The IMM-NRF51822 micro-module has exposed the SWD (Serial Wire Debug) pins SWDIO & SWCLK, see I/O layout picture above. Thanks for. org Project. 00039\ccsv6\ccs_base\msp430\include_gcc\msp430f5438a. A lot of the power of C++ comes from the STL, the C++ Standard Library. Libraries are searched by default in the libraries path ( gcc --print-search-dirs). 0 environment and unzipped it. make reads in rules (specified as a list of target entries) from a user created Makefile. You most probably did not configure properly the toolchain path, and CDT cannot start the discovery process. Troubles compiling or linking programs using libxml2. You will therefore need to include the paths to these files using the -J compiler switch. Typically, header files of a library will be placed in a different directory than your application's code. path-autocomplete. Make sure to include the path to gdb in your path before starting the NetBeans IDE. #include "boost/random. Linuxのgccで、インクルードファイルやライブラリのパスを設定する方法が知りたいのですが、gccについて詳しい書籍やサイトがありましたら、教えてください。gccとccの違いも知りたいです。例)#include "example - UNIX・Linux 解決済 | 教えて!goo. It seems the initial release of gcc-3. Ah, I'm using Windows 10 pro version. 0, and Linux v5. 1 million software developers love Qt because they can build powerful cross-platform applications - modular C++ class library, declarative design & pro IDE. Cookie Notice. make reads in rules (specified as a list of target entries) from a user created Makefile. The LLVM Project is a collection of modular and reusable compiler and toolchain technologies. compiler include path setting. Commented: 2001-08-19. The CC version check failed. default include paths are set in /src/gcc/cppdefault. Tutorial of gcc and gdb. Make it split the path, at configure time, into a prefix part and a path part, so gcc will remember /mingw and /include separately. To pass multiple arguments such as -Xmaxerrs 1000 (which are actually two arguments) you have to use compilerArguments. Code::Blocks is a free C, C++ and Fortran IDE built to meet the most demanding needs of its users. The latest version is gcc/g++ 4. piece tells gcc to look in the current directory in addition to the other library directories for finding libmylib. Debugging will still work without adding the paths and symbols manually as Eclipse is a pure IDE and gcc and gdb take care of the build and debug. In a multiarch world, this is. edu, which has the connected SAPCs needed for running your programs. Both the newer gcc and intel compilers are in my home directory (non-root) I use C++11 in my codes, so obviously i use -std=c++11 flag for compiling. It uses Mingw port of GCC (GNU Compiler Collection) as it's compiler. Programs, when they internally list the shared libraries they need, should only list the soname they need. This is in addition to the other environment variables that are updated which include PATH, and LD_LIBRARY_PATH. How can I fix this? The GCC compiler is installed in my computer. c in the example below), and (2) tell the compiler to link in the code from the library. (Is that quite true? How does Clang do it?) Accordi. If GCC_COMPARE_DEBUG is defined to a string starting with a dash, then it is used for opts, otherwise the default -gtoggle is used. Zero or more of the following:. Verify the GCC installation by listing the version of gcc, g++ and gdb :. The preprocessor outputs one make rule containing the object file name for that source file, a colon, and the names of all the included files, including those coming from -include or -imacros command line options. Gcc linker search path order I'm using a -L option to point to the version that I wish to link against but gcc still seems to choose the installed version. When you do an include with quotes, e. The best way to use LD_LIBRARY_PATH is to set it on the command line or script immediately before executing the program. The Eclipse Foundation - home to a global community, the Eclipse IDE, Jakarta EE and over 350 open source projects, including runtimes, tools and frameworks. path, so that it can find support modules, such as gccutils. The exact search directory list depends on the target system, how GCC is configured, and where. For the angle-bracket form #include , the preprocessor's default behavior is to look only in the standard system directories. String that represents a location inside a project directory. On Fri, 27 Feb 2004, Tibor Kendl wrote: > Dear mailing list members! > I'd like to know, how do you solve this problem on your own systems. Raspberry Pi - Install GCC 9 and compile C++17 programs Posted on December 8, 2017 by Paul. 1) relied on the system path of the development system to execute the required tools (avr-gcc, avr-size, make etc. It is apparent that the IDE installation package does not add the path to to the environment for the "gcc" tools as possibly it should. Updated 28 June 2019. Create a folder called prebuild in your Android project root folder. If you use double-quotes (e. Eclipse uses the compiler to get the builtin include paths and symbols. ABI compatibility with gcc's libstdc++ for some low-level features such as exception objects, rtti and memory allocation. Minimal memory use. * WebProcess/WebProcess. Now you should put the path into the path environment variable. Note: It is possible to use scl enable for a specific. o file, then link the. Concepts promise to fundamentally change how we write templated C++ code. Libraries are searched by default in the libraries path ( gcc --print-search-dirs). 8 was included in Red Hat Enterprise Linux 7. bashrc 파일 마지막 부분에 아래 커맨드를 추가한다. Compile Using GNU GCC From Visual Studio: This instructable will show how to use Visual Studio 2013 Community Technology Edition to compile a program using a GNU GCC compiler toolchain. You have to adapt it to your compiler. mpirun is a wrapper script for launching mpi programs that is also provided by MPI implementers. Clone via HTTPS Clone with Git or checkout with SVN using the repository's web address. 00039\ccsv6\ccs_base\msp430\include_gcc\msp430f5438a. It uses Mingw port of GCC (GNU Compiler Collection) as it's compiler. 제 경험상 학교에서는 기본적인 -o 옵션정도, 회사에서는 Makefile 에 의한 자동 컴파일을 하기때문에 많은 분들이 컴파일 옵션을 잘 모르시는것 같습니다. CPATH: For searching the include-paths for headers. Note: It is possible to use scl enable for a specific. It is apparent that the IDE installation package does not add the path to to the environment for the "gcc" tools as possibly it should. In this article I will show you how to install GCC 9 on your Raspberry Pi system and how to compile C++17 programs. To solve this problem, the GCC back-end may provide a secondary OS multilib suffix which is used in place of the primary multilib suffix for all library directories derived from *system* paths as opposed to GCC paths. I've written a c++ code that has dependencies on gsl (gnu scientific library) and I had thought that setting the compiler to include the path to link with your libraries involves adding a simple line. If you used an unfriendly installer, which already updated the system path without asking, you should manually fix this situation, and remove the toolchain path from the system path. I do not want to go into the hairy details. It's a little hard to compile a program without it. Thanks for. GNU Toolchain (GCC, Binutils, GDB, newlib) with support for Arm Cortex-M and Cortex-R embedded processors. On many systems, /usr/local comes before /usr in PATH. set_include_path. MinGW-w64 gcc compilier improperly linked with Learn more about mingw, gcc, matlab. Project Explorer DID display the paths under Includes. 12 and later include both 32 bit and 64 bit tools. c Note that the include paths do not need to actually exists. If it is missing (and the first element other than the root name is a file name), then the path is relative and requires another path as the starting location to resolve to a file name. The special character, PATH_SEPARATOR, is target-dependent and determined at build time. In windows/preferences page" c++ - build - settings" tab Discovery, and "GCC builtin compiler settings" click" clear entries". if you see the following output as shown in the picture below the mingw is installed successfully. Inclusion of "-isystem /usr/include" likely stemming from this revision causes build failures in some packages when building with GCC-6. Re: changing default gcc include path From: Jakub Jelinek [ Date Prev ][ Date Next ] [ Thread Prev ][ Thread Next ] [ Thread Index ] [ Date Index ] [ Author Index ]. I have Ubuntu system and gcc/g++-4. The simplest way to install gccgo is to install a GCC binary release built to include Go support. TDM-GCC is pleased to present new toolchains based on GCC 5. I hope you know how to do this under winXP! Be sure, it's the only compiler in your path. I Need the Kernel Source. The usual way to run GCC is to run the executable called gcc, or machine-gcc when cross-compiling, or machine-gcc-version to run a specific version of GCC. How to determine clang's system include dirs, to set in ASTVisitor?. In windows/preferences page" c++ - build - settings" tab Discovery, and "GCC builtin compiler settings" click" clear entries". What happens if you remove that obvious CPLUS_INCLUDE_PATH, and check the makefile/configure script for any -I /usr/include and subsequently remove them? Not on my arch would test that myself otherwise. If you used an unfriendly installer, which already updated the system path without asking, you should manually fix this situation, and remove the toolchain path from the system path. gcc -M test. To install the gcc and g++ compilers, you will need the build-essential package. gcc -I adds include directory of header files. See the cmake-buildsystem(7) manual for more on defining buildsystem properties. Created on 2018-07-14 16:25 by jayanthkoushik, last changed 2018-07-15 09:29 by jayanthkoushik. Specifies a path which will be used both by FIND_FILE() and FIND_PATH(). Both the newer gcc and intel compilers are in my home directory (non-root) I use C++11 in my codes, so obviously i use -std=c++11 flag for compiling. edu, which has the connected SAPCs needed for running your programs. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. The standard paths will still be searched, but only after the list of paths in LD_LIBRARY_PATH has been exhausted. I was barely able to hack it together myself and there are still a few details I am not 100% clear on. icpc employs the g++ which is found on PATH to find include files, presumably by something like. so or the C or maths libraries, send mail to [email protected] Using Boost C++ libraries with gcc / g++ under Windows. Go to Cross GCC Linker->Miscellaneous, and under Linker flags, add -T C:\CCStudio_v6. How to determine clang's system include dirs, to set in ASTVisitor?. o files (along with any. Program "arm-none-eabi-gcc" not found in PATH. Minimal memory use. Moondancer. The C/C++ extension does not include a C++ compiler or debugger. 0 visual studio 2017 version 15. How to Link Static Library in C/C++ using GCC compiler? This tutorial presents simple ways to create and use the static library in C/C++ using GCC compiler. Re: changing default gcc include path From: Jakub Jelinek [ Date Prev ][ Date Next ] [ Thread Prev ][ Thread Next ] [ Thread Index ] [ Date Index ] [ Author Index ]. Creating Libraries :: Shared Library Setup. To set this compiler option programmatically. 6) does not exactly match the current compiler (gcc 4. #include "sub/test. Copy C:\MinGW\bin. GetCurrentDirectory(). How to add a default include path for gcc in linux - The GNU Compiler Collection (GCC) is a compiler system produced by the GNU Project supporting various programming languages. 3 Including Other Makefiles. Reopen Command prompt window, and type gcc. It includes the GNU Compiler (GCC) and is available free of charge directly from Arm for embedded software development on Windows, Linux and Mac OS X operating systems. In the response file, msys2 path fails (but should work, according to gcc man page). is included so that gcc will look in the current directory (. json reference. a file to the prebuild folder and also copy the include folder. It seems the initial release of gcc-3. The plugin automatically adds the absolute path to its own directory to the end of its sys. default include paths are set in /src/gcc/cppdefault. There are a variety of toolchains you can install on Windows for compiling C and C++ applications. Compiling GTK+ Applications on UNIX. Add directory to QUOTE include search path-isysroot¶ Set the system root directory (usually /)-isystem¶ Add directory to SYSTEM include search path-isystem-after¶ Add directory to end of the SYSTEM include search path-ivfsoverlay¶ Overlay the virtual filesystem described by file over the real file system. unset LIBRARY_PATH CPATH C_INCLUDE_PATH PKG_CONFIG_PATH CPLUS_INCLUDE_PATH INCLUDE. c files need to be recompiled and turned into. Dev-C++ can also be used in combination with Cygwin or any other GCC based compiler. View Notes - Makefile from CS 243 at Indiana University, Purdue University Indianapolis. For more details about installing MSYS2 check out Install gcc compiler on Windows with MSYS2 for C/C++. The exact search directory list depends on the target system, how GCC is configured, and where. Note: Git Bash in Windows cannot behave exactly the same as a linux bash. ) and builds a hierarchical tree diagram of all dependent modules. Raspberry Pi - Install GCC 9 and compile C++17 programs Posted on December 8, 2017 by Paul. This is part of a series of articles on the nRF51. 1: Right click on your project and click "Properties" Select "C/C++ Build" in the sidebar. You only need to add to the Include path array setting if your program includes header files that are not in your workspace or in the standard library path. make reads in rules (specified as a list of target entries) from a user created Makefile. QEMU Emulator. Note that the path is relative, but you can obviously use absolute paths, and more than one path at a time: gcc -c -I. I copy pasted your code into mpi_app. However, you shouldn't put them "anywhere you want", either put them in your home folder or somewhere that isn't a system path (not on the root partition). I'm trying to programmatically find the #include path on Linux, which as I understand it, in practice means finding what GCC considers it to be. gcc -M test. It seems the initial release of gcc-3. Fast compile times. GCC has built-in include paths that are used even if my compiler flags don’t specify them. GCC binary releases are available from various websites and are typically included as part of GNU/Linux distributions. TensorFlow is open source. Otherwise the configuration scripts may fail. triggerOutsideStrings boolean - if true it will trigger the autocomplete outside of quotes. His background delivery experience ranging from software systems through to civil engineering and construction projects have, and will prove a valuable mix of skills for the development, integration and commissioning of complex infrastructures. -I, --include-directory , --include-directory=¶ Add directory to include search path-I-, --include-barrier¶Restrict all prior -I flags to double-quoted inclusion and remove current directory from include path. I have Ubuntu system and gcc/g++-4. W here is my GNU C compiler? Where does the GNU C (gcc) compiler reside in the RHEL / Fedora / Debian / Ubuntu / CentOS Linux installation? How do I install GNU c/c++ compiler in Linux operating systems? The GNU Compiler Collection (GCC) is a compiler system. Any suggestion on the best way to include all the paths for header files using GCC and Eclipse plugin for GNU GCC ARM? Offline Manoel De Souza over 1 year ago. Setting Up Include Paths and Macros for C/C++ Indexer. 0a42375--- /dev/null +++ b/Makefile @@ -0,0 +1 @@ +include. Josh Stern wrote: > Use of the C99 header in a C library header that > is then used within a C++ program causes compile/linkage > problems. That's how most projects deal with that kind of issues. Conversely, when you create a shared library, you only create the library with a specific filename (with more detailed version information). After this command is done you will find a complete OpenTTD ready for distribution in the ~//bundle folder. #include "neuron. text data bss dec hex filename 860126 486 7272 867884 d3e2c busybox-1. Normally one of them, limits. Equipped with TensorFlow, many complicated machine learning models, as well as general mathematical problems could be programmed easily and launched to hierarchical and efficient architectures (multi-CPUs and multi-GPUs). 2 869074 516 7364 876954 d619a busybox-1. Search/Indexing, edit, compile and debug. Since I've started my include with "sub\" this points to a subfolder relative to the folder where the file doing the include is locates. TensorFlow offers an excellent framework for executing mathematical operations. mk $(bar) is equivalent to include foo a. json file, your include paths and compile flags configuration settings (described below) are ignored. See the cmake-buildsystem(7) manual for more on defining buildsystem properties. 0 is installed and the filesystem file is not in this folder. A typical compilation command for a source file example. 0\home\\trunk in this example). For static library file libmath. #include "sub/test. (view as text). It is searched after paths specified in -I options. I want to include some of the Arduino libraries in my project, like Wire. include a GCC toolchain within them in the linux-devkit directory. If a -rpath option is used, the runtime search path will be formed exclusively using the -rpath options, ignoring the -L options. The same compilation command with g++ would use the environment variables CPLUS_INCLUDE_PATH and LIBRARY_PATH. d files in the makefile (like Chris wrote above). The IMM-NRF51822 micro-module has exposed the SWD (Serial Wire Debug) pins SWDIO & SWCLK, see I/O layout picture above. His background delivery experience ranging from software systems through to civil engineering and construction projects have, and will prove a valuable mix of skills for the development, integration and commissioning of complex infrastructures. (Is that quite true? How does Clang do it?) Accordi. ABI compatibility with gcc's libstdc++ for some low-level features such as exception objects, rtti and memory allocation. Could you solve this for me? I'm waiting for your answer. 0 Foreword The PowerPC Embedded Application Binary Interface, or EABI, was created to meet the unique needs of PowerPC embedded applications, specifically minimizing memory usage while main-. In this article I will show you how to install GCC 9 on your Raspberry Pi system and how to compile C++17 programs. htaccess files to set the include path, PHP must be installed as an Apache module. libc++ is a new implementation of the C++ standard library, targeting C++11 and above. The path to the SFML headers (/include) to the Compiler search directories; The path to the SFML libraries (/lib) to the Linker search directories; These paths are the same in both Debug and Release configuration, so you can set them globally for your project. How to set the include paths for gcc in a Managed Make project in Eclipse 3. To install GCC, the trick is to install MinGW installation manager. When I compile a C program using “gcc filename. exe my_mpi_program. #include then use-MM. It asks for an essay on the. Here is another way to state it. A lot of the power of C++ comes from the STL, the C++ Standard Library. a use -lmath:. Posted on 06/17/2007 9:39 PM Getting back into programming is being difficult for me. a file in build/lib and a whole pile of headers in build/include. For example, when I have:. Is there a way to have CMake include_directories include the system directory prefix with equals(=) character? So that I can have gcc prefix the associated dirs with -isysroot flag for the cross compilation. If a -rpath option is used, the runtime search path will be formed exclusively using the -rpath options, ignoring the -L options. Address space is a very limiting factor for Cygwin. How to set include path once for nvcc? Reply. Note that some combinations (for example, -x cpp-output -E) instruct gcc to do nothing at all. If you dont want the system includes like. Download: MinGW (Minimalist GNU for Windows) Setelah MinGW di download, set path instalannya agar bisa dijalankan dari Command Prompt dari lokasi path mana saja. Make sure to include the path to gdb in your PATH before starting the NetBeans IDE. This compiles the two. enableFolderTrailingSlash boolean - if true it will add a slash after the insertion of a folder path that will trigger the autocompletion. See the Build Tools page. I do not want to go into the hairy details. Verifying Paths. Both a GCC-compatible compiler driver (clang) and an MSVC-compatible compiler driver (clang-cl. I believe somehow I set this up long ago but I have no idea how this is controlled and would like to make it automatic with the original filename instead of a. This will also install GNU make. Eclipse uses the compiler to get the builtin include paths and symbols. Ask Question then you will have to modify it so as to put /usr/local/bin ahead of any other PATH component where gcc and all its the making alias or linking to different gcc binaries will make them use their own include before the default system include folder. Address space is a very limiting factor for Cygwin. The C Preprocessor: Search Path. 2 and CDT 3. Any suggestion on the best way to include all the paths for header files using GCC and Eclipse plugin for GNU GCC ARM? Offline Manoel De Souza over 1 year ago. To make what you have work try setting C_INCLUDE_PATH and/or CPLUS_INCLUDE_PATH to the location of the stdio. c file is newer than the. 1) separately (See "How to install MinGW"), and configured the compiler's and debugger's path to the installed MinGW as in the above step. Install Minimalist GNU For Windows into C:\MinGW. $ gcc -Wall dbmain. September 2002. get(objValue); Should be:. `Makevars' can also be used to set flags for the linker, for example `-L' and `-l' options, via PKG_LIBS. Why? Some users seem to set this environment variable because of bad advice from other users or badly linked code that they do not know how to fix. -- Check for working CXX compiler: /usr/local/bin/g++48 -- works. I want to include some of the Arduino libraries in my project, like Wire. gcc -L looks in directory for library files. I've confirmed this, in that, if i replace any #include path that gives an error, by the it's. h: No such file or directory. I wopuld look at ports systems like macports or Homebrew to see how they manage any changes this build needs – user151019 Jul 6 '18 at 9:15. 0 has a problem with the optimizer which miscompiles the URI module. The directive is a line in the makefile that looks like this: include filenames. Go to Cross GCC Linker->Libraries, and under Library search path (-L), add the path to \ccs_base\msp430\include_gcc. This will ensure that everything builds correctly. If you need to do the same in Windows, you may try CygWin. Follow the instruction to install it. [William Rowe] *) Fix a segfault with mod_include when r->path_info is not set (which is the case with mod_proxy). See the cmake-generator-expressions(7) manual for available expressions. We expect that most people who build these binaries will include Go support. Linking is the process of joining one or more object code files together with one or more of the system libraries. Syntax $ gcc [options] [source files] [object files] [-Ldir] -llibname [-o outfile] Link -l with library name without the lib prefix and the. What I want is something similar to the way gcc searches for include directories: `gcc -print-prog-name=cc1` -v or. 2008-05-09. CPLUS_INCLUDE_PATH and C_INCLUDE_PATH are pretty much the same. In order to use. ARM is nowadays the most widespread architecture (thanks to the diffusion of embedded systems in the last years), and GCC is used by many hardware and software manufacturers as foundation tool for their platform. In short, gcc can automatically create. -lmylib The -L. If PHP is compiled as a CGI binary, you can set the include path in a custom php. In the previous post we talked about Red Bear Lab BLE Nano platform and how to program it from mbed or Arduino. The GNU Embedded Toolchain for Arm is a ready-to-use, open source suite of tools for C, C++ and Assembly programming targeting Arm Cortex-M and Cortex-R family of processors. RIYADH: Citizens of Gulf Cooperation Council (GCC) countries have been temporarily banned from entering Saudi Arabia’s holy cities Makkah and Madinah, the Kingdom’s foreign ministry said in a. How to set gcc 4.