644d38570a
glibc has an add-ons mechanism to allow additional software to be integrated into the glibc build. Such add-ons may be within the glibc source tree, or outside it at a path passed to the --enable-add-ons configure option. localedata and crypt were once add-ons, distributed in separate release tarballs, but long since stopped using that mechanism. Linuxthreads was always an add-on. Ports spent some time as an add-on with separate release tarballs, then was first moved into the glibc source tree, then had its sysdeps files moved into the main sysdeps hierarchy so the add-ons mechanism was no longer used. NPTL spent some time as an add-on in the main glibc tree before stopping using the add-on mechanism. libidn used to have separate release tarballs but no longer does so, but still uses the add-ons mechanism within the glibc source tree. Various other software has supported building with the add-ons mechanism at times in the past, but I don't think any is still widely used. Add-ons involve significant, little-used complexity in the glibc build system, and make it hard to understand what the space of possible glibc configurations is. This patch removes the add-ons mechanism. libidn is now built via the Subdirs mechanism to cause any configuration using sysdeps/unix/inet to build libidn; HAVE_LIBIDN (which effectively means shared libraries are available) is now defined via sysdeps/unix/inet/configure. Various references to add-ons around the source tree are removed (in the case of maint.texi, the example list of sysdeps directories is still very out of date). Externally maintained ports should now put their files in the normal sysdeps directory structure rather than being arranged as add-ons; they probably need to change e.g. elf.h anyway, rather than actually being able to work just as a drop-in subtree. Hurd libpthread should be arranged similarly to NPTL, so some files might go in a hurd-pthreads (or similar) top-level directory in glibc, while sysdeps files should go in the normal sysdeps directory structure (possibly in hurd or hurd-pthreads subdirectories, just as there are nptl subdirectories in the sysdeps tree). Tested for x86_64, and with build-many-glibcs.py. * configure.ac (--enable-add-ons): Remove option. (machine): Do not mention add-ons in comment. (LIBC_PRECONFIGURE): Likewise. (add_ons): Remove variable and sanity checks and logic to locate add-ons. (add_ons_automatic): Remove variable. (configured_add_ons): Likewise. (add_ons_sfx): Likewise. (add_ons_pfx): Likewise. (add_on_subdirs): Likewise. (sysnames_add_ons): Likewise. Remove loop over add-ons and consideration of add-ons in Implies handling. (sysdeps_add_ons): Likewise. * configure: Regenerated. * libidn/configure.ac: Remove. * libidn/configure: Likewise. * sysdeps/unix/inet/configure.ac: New file. * sysdeps/unix/inet/configure: New generated file. * sysdeps/unix/inet/Subdirs: Add libidn. * Makeconfig (sysdeps-srcdirs): Remove variable. (+sysdep_dirs): Do not include $(sysdeps-srcdirs). ($(common-objpfx)config.status): Do not depend on add-on files. ($(common-objpfx)shlib-versions.v.i): Do not mention add-ons in comment. (all-subdirs): Do not include $(add-on-subdirs). * Makefile (dist-prepare): Do not use $(sysdeps-add-ons). * config.make.in (add-ons): Remove variable. (add-on-subdirs): Likewise. (sysdeps-add-ons): Likewise. * manual/Makefile (add-chapters): Remove. ($(objpfx)texis): Do not depend on $(add-chapters). (nonexamples): Do not handle $(add-chapters). (examples): Do not handle $(add-ons). (chapters.% top-menu.%): Do not pass '$(add-chapters)' to libc-texinfo.sh. * manual/install.texi (Installation): Do not mention add-ons. (--enable-add-ons): Do not document configure option. * INSTALL: Regenerated. * manual/libc-texinfo.sh: Do not handle $2 add-ons argument. * manual/maint.texi (Hierarchy Conventions): Do not mention add-ons. * scripts/build-many-glibcs.py (Glibc.build_glibc): Do not use --enable-add-ons. * scripts/gen-sorted.awk: Do not handle Subdirs files from add-ons. * scripts/test-installation.pl: Do not handle glibc-compat add-on. * sysdeps/nptl/Makeconfig: Do not mention add-ons in comment.
This directory contains the sources of the GNU C Library. See the file "version.h" for what release version you have. The GNU C Library is the standard system C library for all GNU systems, and is an important part of what makes up a GNU system. It provides the system API for all programs written in C and C-compatible languages such as C++ and Objective C; the runtime facilities of other programming languages use the C library to access the underlying operating system. In GNU/Linux systems, the C library works with the Linux kernel to implement the operating system behavior seen by user applications. In GNU/Hurd systems, it works with a microkernel and Hurd servers. The GNU C Library implements much of the POSIX.1 functionality in the GNU/Hurd system, using configurations i[4567]86-*-gnu. The current GNU/Hurd support requires out-of-tree patches that will eventually be incorporated into an official GNU C Library release. When working with Linux kernels, this version of the GNU C Library requires Linux kernel version 3.2 or later. Also note that the shared version of the libgcc_s library must be installed for the pthread library to work correctly. The GNU C Library supports these configurations for using Linux kernels: aarch64*-*-linux-gnu alpha*-*-linux-gnu arm-*-linux-gnueabi hppa-*-linux-gnu Not currently functional without patches. i[4567]86-*-linux-gnu x86_64-*-linux-gnu Can build either x86_64 or x32 ia64-*-linux-gnu m68k-*-linux-gnu microblaze*-*-linux-gnu mips-*-linux-gnu mips64-*-linux-gnu powerpc-*-linux-gnu Hardware or software floating point, BE only. powerpc64*-*-linux-gnu Big-endian and little-endian. s390-*-linux-gnu s390x-*-linux-gnu sh[34]-*-linux-gnu sparc*-*-linux-gnu sparc64*-*-linux-gnu tilegx-*-linux-gnu tilepro-*-linux-gnu If you are interested in doing a port, please contact the glibc maintainers; see http://www.gnu.org/software/libc/ for more information. See the file INSTALL to find out how to configure, build, and install the GNU C Library. You might also consider reading the WWW pages for the C library at http://www.gnu.org/software/libc/. The GNU C Library is (almost) completely documented by the Texinfo manual found in the `manual/' subdirectory. The manual is still being updated and contains some known errors and omissions; we regret that we do not have the resources to work on the manual as much as we would like. For corrections to the manual, please file a bug in the `manual' component, following the bug-reporting instructions below. Please be sure to check the manual in the current development sources to see if your problem has already been corrected. Please see http://www.gnu.org/software/libc/bugs.html for bug reporting information. We are now using the Bugzilla system to track all bug reports. This web page gives detailed information on how to report bugs properly. The GNU C Library is free software. See the file COPYING.LIB for copying conditions, and LICENSES for notices about a few contributions that require these additional notices to be distributed. License copyright years may be listed using range notation, e.g., 1996-2015, indicating that every year in the range, inclusive, is a copyrightable year that would otherwise be listed individually.