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This is the complete rework of the feature tests macros for better compatibility with GNU libc, primarily based on the Linux man pages documentation: http://man7.org/linux/man-pages/man7/feature_test_macros.7.html The previous implementation was flawed in its approach that macros were often used to hide symbols if defined (e.g. !defined __STRICT_ANSI__ or !defined _POSIX_SOURCE), whereas the approach of glibc is that these macros make symbols available when defined (e.g. defined _BSD_SOURCE, or as used internally, #if __BSD_VISIBLE). As much open-source software is written with glibc in mind, this necessitated patching numerous packages just to compile. In particular, __STRICT_ANSI__ (which is defined by gcc -ansi or -std=c*) was given too much importance. This implementation limits the influence of __STRICT_ANSI__ to controlling the default when no other feature test macros are defined, and to the inclusion of <alloca.h> in <stdlib.h> as documented. These are the only places where __STRICT_ANSI__ should be tested. The following macros are now accepted: _ATFILE_SOURCE, _BSD_SOURCE, _DEFAULT_SOURCE, _ISOC99_SOURCE, _ISOC11_SOURCE, _LARGEFILE_SOURCE, _SVID_SOURCE, _XOPEN_SOURCE_EXTENDED. The existing __*_VISIBLE internal macros have been kept mostly compatible with the original BSD implementation, with some changes to the criteria which controls them. Several more macros in this style have been added where needed for concision or accuracy. Enabling C++11 or newer in the compiler also enables C99 and C11 functions. Doing so should help move away from the need to define _GNU_SOURCE in g++ for _GLIBCXX_USE_C99 support as on Linux: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51749 Signed-off-by: Yaakov Selkowitz <yselkowi@redhat.com>
README for GNU development tools This directory contains various GNU compilers, assemblers, linkers, debuggers, etc., plus their support routines, definitions, and documentation. If you are receiving this as part of a GDB release, see the file gdb/README. If with a binutils release, see binutils/README; if with a libg++ release, see libg++/README, etc. That'll give you info about this package -- supported targets, how to use it, how to report bugs, etc. It is now possible to automatically configure and build a variety of tools with one command. To build all of the tools contained herein, run the ``configure'' script here, e.g.: ./configure make To install them (by default in /usr/local/bin, /usr/local/lib, etc), then do: make install (If the configure script can't determine your type of computer, give it the name as an argument, for instance ``./configure sun4''. You can use the script ``config.sub'' to test whether a name is recognized; if it is, config.sub translates it to a triplet specifying CPU, vendor, and OS.) If you have more than one compiler on your system, it is often best to explicitly set CC in the environment before running configure, and to also set CC when running make. For example (assuming sh/bash/ksh): CC=gcc ./configure make A similar example using csh: setenv CC gcc ./configure make Much of the code and documentation enclosed is copyright by the Free Software Foundation, Inc. See the file COPYING or COPYING.LIB in the various directories, for a description of the GNU General Public License terms under which you can copy the files. REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info on where and how to report problems.