Edit File: lang.m4
# This file is part of Autoconf. -*- Autoconf -*- # Programming languages support. # Copyright (C) 2000-2002, 2004-2012 Free Software Foundation, Inc. # This file is part of Autoconf. This program is free # software; you can redistribute it and/or modify it under the # terms of the GNU General Public License as published by the # Free Software Foundation, either version 3 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # Under Section 7 of GPL version 3, you are granted additional # permissions described in the Autoconf Configure Script Exception, # version 3.0, as published by the Free Software Foundation. # # You should have received a copy of the GNU General Public License # and a copy of the Autoconf Configure Script Exception along with # this program; see the files COPYINGv3 and COPYING.EXCEPTION # respectively. If not, see <http://www.gnu.org/licenses/>. # Written by David MacKenzie, with help from # Franc,ois Pinard, Karl Berry, Richard Pixley, Ian Lance Taylor, # Roland McGrath, Noah Friedman, david d zuhn, and many others. # Table of Contents: # # 1. Language selection # and routines to produce programs in a given language. # # 2. Producing programs in a given language. # # 3. Looking for a compiler # And possibly the associated preprocessor. # # 3a. Computing EXEEXT and OBJEXT. # # 4. Compilers' characteristics. ## ----------------------- ## ## 1. Language selection. ## ## ----------------------- ## # AC_LANG_CASE(LANG1, IF-LANG1, LANG2, IF-LANG2, ..., DEFAULT) # ------------------------------------------------------------ # Expand into IF-LANG1 if the current language is LANG1 etc. else # into default. m4_define([AC_LANG_CASE], [m4_case(_AC_LANG, $@)]) # _AC_LANG_DISPATCH(MACRO, LANG, ARGS) # ------------------------------------ # Call the specialization of MACRO for LANG with ARGS. Complain if # unavailable. m4_define([_AC_LANG_DISPATCH], [m4_ifdef([$1($2)], [m4_indir([$1($2)], m4_shift2($@))], [m4_fatal([$1: unknown language: $2])])]) # _AC_LANG_SET(OLD, NEW) # ---------------------- # Output the shell code needed to switch from OLD language to NEW language. # Do not try to optimize like this: # # m4_defun([_AC_LANG_SET], # [m4_if([$1], [$2], [], # [_AC_LANG_DISPATCH([AC_LANG], [$2])])]) # # as it can introduce differences between the sh-current language and the # m4-current-language when m4_require is used. Something more subtle # might be possible, but at least for the time being, play it safe. m4_defun([_AC_LANG_SET], [_AC_LANG_DISPATCH([AC_LANG], [$2])]) # AC_LANG(LANG) # ------------- # Set the current language to LANG. m4_defun([AC_LANG], [_AC_LANG_SET(m4_ifdef([_AC_LANG], [m4_defn([_AC_LANG])]), [$1])dnl m4_define([_AC_LANG], [$1])]) # AC_LANG_PUSH(LANG) # ------------------ # Save the current language, and use LANG. m4_defun([AC_LANG_PUSH], [_AC_LANG_SET(m4_ifdef([_AC_LANG], [m4_defn([_AC_LANG])]), [$1])dnl m4_pushdef([_AC_LANG], [$1])]) # AC_LANG_POP([LANG]) # ------------------- # If given, check that the current language is LANG, and restore the # previous language. m4_defun([AC_LANG_POP], [m4_ifval([$1], [m4_if([$1], m4_defn([_AC_LANG]), [], [m4_fatal([$0($1): unexpected current language: ]m4_defn([_AC_LANG]))])])dnl m4_pushdef([$0 OLD], m4_defn([_AC_LANG]))dnl m4_popdef([_AC_LANG])dnl _AC_LANG_SET(m4_defn([$0 OLD]), m4_defn([_AC_LANG]))dnl m4_popdef([$0 OLD])dnl ]) # AC_LANG_SAVE # ------------ # Save the current language, but don't change language. AU_DEFUN([AC_LANG_SAVE], [[AC_LANG_SAVE]], [Instead of using `AC_LANG', `AC_LANG_SAVE', and `AC_LANG_RESTORE', you should use `AC_LANG_PUSH' and `AC_LANG_POP'.]) AC_DEFUN([AC_LANG_SAVE], [m4_pushdef([_AC_LANG], _AC_LANG)dnl AC_DIAGNOSE([obsolete], [The macro `AC_LANG_SAVE' is obsolete. You should run autoupdate.])]) # AC_LANG_RESTORE # --------------- # Restore the current language from the stack. AU_DEFUN([AC_LANG_RESTORE], [AC_LANG_POP($@)]) # _AC_LANG_ABBREV # --------------- # Return a short signature of _AC_LANG which can be used in shell # variable names, or in M4 macro names. m4_defun([_AC_LANG_ABBREV], [_AC_LANG_DISPATCH([$0], _AC_LANG, $@)]) # _AC_LANG_PREFIX # --------------- # Return a short (upper case) signature of _AC_LANG that is used to # prefix environment variables like FLAGS. m4_defun([_AC_LANG_PREFIX], [_AC_LANG_DISPATCH([$0], _AC_LANG, $@)]) # AC_LANG_ASSERT(LANG) # -------------------- # Current language must be LANG. m4_defun([AC_LANG_ASSERT], [m4_if(_AC_LANG, $1, [], [m4_fatal([$0: current language is not $1: ] _AC_LANG)])]) # AC_LANG_DEFINE(NAME, ABBREV, PREFIX, COMPILER-VAR, COPY-FROM, SHELL-VARS) # ------------------------------------------------------------------------- # Define a language referenced by AC_LANG(NAME), with cache variable prefix # ABBREV, Makefile variable prefix PREFIX and compiler variable COMPILER-VAR. # AC_LANG(NAME) is defined to SHELL-VARS, other macros are copied from language # COPY-FROM. Even if COPY-FROM is empty, a default definition is provided for # language-specific macros AC_LANG_SOURCE(NAME) and AC_LANG_CONFTEST(NAME). m4_define([AC_LANG_DEFINE], [m4_define([AC_LANG($1)], [$6])] [m4_define([_AC_LANG_ABBREV($1)], [$2])] [m4_define([_AC_LANG_PREFIX($1)], [$3])] [m4_define([_AC_CC($1)], [$4])] [m4_copy([AC_LANG_CONFTEST($5)], [AC_LANG_CONFTEST($1)])] [m4_copy([AC_LANG_SOURCE($5)], [AC_LANG_SOURCE($1)])] [m4_copy([_AC_LANG_NULL_PROGRAM($5)], [_AC_LANG_NULL_PROGRAM($1)])] [m4_ifval([$5], [m4_copy([AC_LANG_PROGRAM($5)], [AC_LANG_PROGRAM($1)])] [m4_copy([AC_LANG_CALL($5)], [AC_LANG_CALL($1)])] [m4_copy([AC_LANG_FUNC_LINK_TRY($5)], [AC_LANG_FUNC_LINK_TRY($1)])] [m4_copy([AC_LANG_BOOL_COMPILE_TRY($5)], [AC_LANG_BOOL_COMPILE_TRY($1)])] [m4_copy([AC_LANG_INT_SAVE($5)], [AC_LANG_INT_SAVE($1)])] [m4_copy([_AC_LANG_IO_PROGRAM($5)], [_AC_LANG_IO_PROGRAM($1)])])]) ## ----------------------- ## ## 2. Producing programs. ## ## ----------------------- ## # AC_LANG_CONFTEST(BODY) # ---------------------- # Save the BODY in `conftest.$ac_ext'. Add a trailing new line. AC_DEFUN([AC_LANG_CONFTEST], [m4_pushdef([_AC_LANG_DEFINES_PROVIDED], [m4_warn([syntax], [$0: no AC_LANG_SOURCE call detected in body])])]dnl [_AC_LANG_DISPATCH([$0], _AC_LANG, $@)]dnl [[]_AC_LANG_DEFINES_PROVIDED[]m4_popdef([_AC_LANG_DEFINES_PROVIDED])]) # AC_LANG_CONFTEST()(BODY) # ------------------------ # Default implementation of AC_LANG_CONFTEST. # This version assumes that you can't inline confdefs.h into your # language, and as such, it is safe to blindly call # AC_LANG_DEFINES_PROVIDED. Language-specific overrides should # remove this call if AC_LANG_SOURCE does inline confdefs.h. m4_define([AC_LANG_CONFTEST()], [cat > conftest.$ac_ext <<_ACEOF AC_LANG_DEFINES_PROVIDED[]$1 _ACEOF]) # AC_LANG_DEFINES_PROVIDED # ------------------------ # Witness macro that all prior AC_DEFINE results have been output # into the current expansion, to silence warning from AC_LANG_CONFTEST. m4_define([AC_LANG_DEFINES_PROVIDED], [m4_define([_$0])]) # AC_LANG_SOURCE(BODY) # -------------------- # Produce a valid source for the current language, which includes the # BODY, and as much as possible `confdefs.h'. AC_DEFUN([AC_LANG_SOURCE], [AC_LANG_DEFINES_PROVIDED[]_AC_LANG_DISPATCH([$0], _AC_LANG, $@)]) # AC_LANG_SOURCE()(BODY) # ---------------------- # Default implementation of AC_LANG_SOURCE. m4_define([AC_LANG_SOURCE()], [$1]) # AC_LANG_PROGRAM([PROLOGUE], [BODY]) # ----------------------------------- # Produce a valid source for the current language. Prepend the # PROLOGUE (typically CPP directives and/or declarations) to an # execution the BODY (typically glued inside the `main' function, or # equivalent). AC_DEFUN([AC_LANG_PROGRAM], [AC_LANG_SOURCE([_AC_LANG_DISPATCH([$0], _AC_LANG, $@)])]) # _AC_LANG_NULL_PROGRAM()() # ------------------------- # Default implementation of AC_LANG_NULL_PROGRAM m4_define([_AC_LANG_NULL_PROGRAM()], [AC_LANG_PROGRAM([], [])]) # _AC_LANG_NULL_PROGRAM # --------------------- # Produce valid source for the current language that does # nothing. AC_DEFUN([_AC_LANG_NULL_PROGRAM], [AC_LANG_SOURCE([_AC_LANG_DISPATCH([$0], _AC_LANG, $@)])]) # _AC_LANG_IO_PROGRAM # ------------------- # Produce valid source for the current language that creates # a file. (This is used when detecting whether executables # work, e.g. to detect cross-compiling.) AC_DEFUN([_AC_LANG_IO_PROGRAM], [AC_LANG_SOURCE([_AC_LANG_DISPATCH([$0], _AC_LANG, $@)])]) # AC_LANG_CALL(PROLOGUE, FUNCTION) # -------------------------------- # Call the FUNCTION. AC_DEFUN([AC_LANG_CALL], [m4_ifval([$2], [], [m4_warn([syntax], [$0: no function given])])dnl _AC_LANG_DISPATCH([$0], _AC_LANG, $@)]) # AC_LANG_FUNC_LINK_TRY(FUNCTION) # ------------------------------- # Produce a source which links correctly iff the FUNCTION exists. AC_DEFUN([AC_LANG_FUNC_LINK_TRY], [m4_ifval([$1], [], [m4_warn([syntax], [$0: no function given])])dnl _AC_LANG_DISPATCH([$0], _AC_LANG, $@)]) # AC_LANG_BOOL_COMPILE_TRY(PROLOGUE, EXPRESSION) # ---------------------------------------------- # Produce a program that compiles with success iff the boolean EXPRESSION # evaluates to true at compile time. AC_DEFUN([AC_LANG_BOOL_COMPILE_TRY], [_AC_LANG_DISPATCH([$0], _AC_LANG, $@)]) # AC_LANG_INT_SAVE(PROLOGUE, EXPRESSION) # -------------------------------------- # Produce a program that saves the runtime evaluation of the integer # EXPRESSION into `conftest.val'. AC_DEFUN([AC_LANG_INT_SAVE], [_AC_LANG_DISPATCH([$0], _AC_LANG, $@)]) # _AC_CC # ------ # The variable name of the compiler. m4_define([_AC_CC], [_AC_LANG_DISPATCH([$0], _AC_LANG, $@)]) ## -------------------------------------------- ## ## 3. Looking for Compilers and Preprocessors. ## ## -------------------------------------------- ## # AC_LANG_COMPILER # ---------------- # Find a compiler for the current LANG. Be sure to be run before # AC_LANG_PREPROC. # # Note that because we might AC_REQUIRE `AC_LANG_COMPILER(C)' for # instance, the latter must be AC_DEFUN'd, not just define'd. m4_define([AC_LANG_COMPILER], [AC_BEFORE([AC_LANG_COMPILER(]_AC_LANG[)], [AC_LANG_PREPROC(]_AC_LANG[)])dnl _AC_LANG_DISPATCH([$0], _AC_LANG, $@)]) # AC_LANG_COMPILER_REQUIRE # ------------------------ # Ensure we have a compiler for the current LANG. AC_DEFUN([AC_LANG_COMPILER_REQUIRE], [m4_require([AC_LANG_COMPILER(]_AC_LANG[)], [AC_LANG_COMPILER])]) # _AC_LANG_COMPILER_GNU # --------------------- # Check whether the compiler for the current language is GNU. # # It doesn't seem necessary right now to have a different source # according to the current language, since this works fine. Some day # it might be needed. Nevertheless, pay attention to the fact that # the position of `choke me' on the seventh column is meant: otherwise # some Fortran compilers (e.g., SGI) might consider it's a # continuation line, and warn instead of reporting an error. m4_define([_AC_LANG_COMPILER_GNU], [AC_CACHE_CHECK([whether we are using the GNU _AC_LANG compiler], [ac_cv_[]_AC_LANG_ABBREV[]_compiler_gnu], [_AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [[#ifndef __GNUC__ choke me #endif ]])], [ac_compiler_gnu=yes], [ac_compiler_gnu=no]) ac_cv_[]_AC_LANG_ABBREV[]_compiler_gnu=$ac_compiler_gnu ])])# _AC_LANG_COMPILER_GNU # AC_LANG_PREPROC # --------------- # Find a preprocessor for the current language. Note that because we # might AC_REQUIRE `AC_LANG_PREPROC(C)' for instance, the latter must # be AC_DEFUN'd, not just define'd. Since the preprocessor depends # upon the compiler, look for the compiler. m4_define([AC_LANG_PREPROC], [AC_LANG_COMPILER_REQUIRE()dnl _AC_LANG_DISPATCH([$0], _AC_LANG, $@)]) # AC_LANG_PREPROC_REQUIRE # ----------------------- # Ensure we have a preprocessor for the current language. AC_DEFUN([AC_LANG_PREPROC_REQUIRE], [m4_require([AC_LANG_PREPROC(]_AC_LANG[)], [AC_LANG_PREPROC])]) # AC_REQUIRE_CPP # -------------- # Require the preprocessor for the current language. # FIXME: AU_ALIAS once AC_LANG is officially documented (2.51?). AC_DEFUN([AC_REQUIRE_CPP], [AC_LANG_PREPROC_REQUIRE]) # AC_NO_EXECUTABLES # ----------------- # FIXME: The GCC team has specific needs which the current Autoconf # framework cannot solve elegantly. This macro implements a dirty # hack until Autoconf is able to provide the services its users # need. # # Several of the support libraries that are often built with GCC can't # assume the tool-chain is already capable of linking a program: the # compiler often expects to be able to link with some of such # libraries. # # In several of these libraries, workarounds have been introduced to # avoid the AC_PROG_CC_WORKS test, that would just abort their # configuration. The introduction of AC_EXEEXT, enabled either by # libtool or by CVS autoconf, have just made matters worse. # # Unlike an earlier version of this macro, using AC_NO_EXECUTABLES does # not disable link tests at autoconf time, but at configure time. # This allows AC_NO_EXECUTABLES to be invoked conditionally. AC_DEFUN_ONCE([AC_NO_EXECUTABLES], [m4_divert_push([KILL]) m4_divert_text([DEFAULTS], [ac_no_link=no]) AC_BEFORE([$0], [_AC_COMPILER_EXEEXT]) AC_BEFORE([$0], [AC_LINK_IFELSE]) m4_define([_AC_COMPILER_EXEEXT], [AC_LANG_CONFTEST([_AC_LANG_NULL_PROGRAM]) if _AC_DO_VAR(ac_link); then ac_no_link=no ]m4_defn([_AC_COMPILER_EXEEXT])[ else rm -f -r a.out a.exe b.out conftest.$ac_ext conftest.o conftest.obj conftest.dSYM ac_no_link=yes # Setting cross_compile will disable run tests; it will # also disable AC_CHECK_FILE but that's generally # correct if we can't link. cross_compiling=yes EXEEXT= _AC_COMPILER_EXEEXT_CROSS fi ]) m4_define([AC_LINK_IFELSE], [if test x$ac_no_link = xyes; then AC_MSG_ERROR([link tests are not allowed after AC@&t@_NO_EXECUTABLES]) fi ]m4_defn([AC_LINK_IFELSE])) m4_divert_pop()dnl ])# AC_NO_EXECUTABLES # --------------------------------- # # 3a. Computing EXEEXT and OBJEXT. # # --------------------------------- # # Files to ignore # --------------- # Ignore .d files produced by CFLAGS=-MD. # # On UWIN (which uses a cc wrapper for MSVC), the compiler also generates # a .pdb file # # When the w32 free Borland C++ command line compiler links a program # (conftest.exe), it also produces a file named `conftest.tds' in # addition to `conftest.obj'. # # - *.bb, *.bbg # Created per object by GCC when given -ftest-coverage. # # - *.xSYM # Created on BeOS. Seems to be per executable. # # - *.map, *.inf # Created by the Green Hills compiler. # # - *.dSYM # Directory created on Mac OS X Leopard. # _AC_COMPILER_OBJEXT_REJECT # -------------------------- # Case/esac pattern matching the files to be ignored when looking for # compiled object files. m4_define([_AC_COMPILER_OBJEXT_REJECT], [*.$ac_ext | *.xcoff | *.tds | *.d | *.pdb | *.xSYM | *.bb | *.bbg | *.map | *.inf | *.dSYM]) # _AC_COMPILER_EXEEXT_REJECT # -------------------------- # Case/esac pattern matching the files to be ignored when looking for # compiled executables. m4_define([_AC_COMPILER_EXEEXT_REJECT], [_AC_COMPILER_OBJEXT_REJECT | *.o | *.obj]) # We must not AU define them, because autoupdate would then remove # them, which is right, but Automake 1.4 would remove the support for # $(EXEEXT) etc. # FIXME: Remove this once Automake fixed. AC_DEFUN([AC_EXEEXT], []) AC_DEFUN([AC_OBJEXT], []) # _AC_COMPILER_EXEEXT_DEFAULT # --------------------------- # Check for the extension used for the default name for executables. # # We do this in order to find out what is the extension we must add for # creating executables (see _AC_COMPILER_EXEEXT's comments). # # On OpenVMS 7.1 system, the DEC C 5.5 compiler when called through a # GNV (gnv.sourceforge.net) cc wrapper, produces the output file named # `a_out.exe'. # b.out is created by i960 compilers. # # Start with the most likely output file names, but: # 1) Beware the clever `test -f' on Cygwin, try the DOS-like .exe names # before the counterparts without the extension. # 2) The algorithm is not robust to junk in `.', hence go to wildcards # (conftest.*) only as a last resort. # Beware of `expr' that may return `0' or `'. Since this macro is # the first one in touch with the compiler, it should also check that # it compiles properly. # # The IRIX 6 linker writes into existing files which may not be # executable, retaining their permissions. Remove them first so a # subsequent execution test works. # m4_define([_AC_COMPILER_EXEEXT_DEFAULT], [# Try to create an executable without -o first, disregard a.out. # It will help us diagnose broken compilers, and finding out an intuition # of exeext. AC_MSG_CHECKING([whether the _AC_LANG compiler works]) ac_link_default=`AS_ECHO(["$ac_link"]) | sed ['s/ -o *conftest[^ ]*//']` # The possible output files: ac_files="a.out conftest.exe conftest a.exe a_out.exe b.out conftest.*" ac_rmfiles= for ac_file in $ac_files do case $ac_file in _AC_COMPILER_EXEEXT_REJECT ) ;; * ) ac_rmfiles="$ac_rmfiles $ac_file";; esac done rm -f $ac_rmfiles AS_IF([_AC_DO_VAR(ac_link_default)], [# Autoconf-2.13 could set the ac_cv_exeext variable to `no'. # So ignore a value of `no', otherwise this would lead to `EXEEXT = no' # in a Makefile. We should not override ac_cv_exeext if it was cached, # so that the user can short-circuit this test for compilers unknown to # Autoconf. for ac_file in $ac_files '' do test -f "$ac_file" || continue case $ac_file in _AC_COMPILER_EXEEXT_REJECT ) ;; [[ab]].out ) # We found the default executable, but exeext='' is most # certainly right. break;; *.* ) if test "${ac_cv_exeext+set}" = set && test "$ac_cv_exeext" != no; then :; else ac_cv_exeext=`expr "$ac_file" : ['[^.]*\(\..*\)']` fi # We set ac_cv_exeext here because the later test for it is not # safe: cross compilers may not add the suffix if given an `-o' # argument, so we may need to know it at that point already. # Even if this section looks crufty: it has the advantage of # actually working. break;; * ) break;; esac done test "$ac_cv_exeext" = no && ac_cv_exeext= ], [ac_file='']) AS_IF([test -z "$ac_file"], [AC_MSG_RESULT([no]) _AC_MSG_LOG_CONFTEST AC_MSG_FAILURE([_AC_LANG compiler cannot create executables], 77)], [AC_MSG_RESULT([yes])]) AC_MSG_CHECKING([for _AC_LANG compiler default output file name]) AC_MSG_RESULT([$ac_file]) ac_exeext=$ac_cv_exeext ])# _AC_COMPILER_EXEEXT_DEFAULT # _AC_COMPILER_EXEEXT_CROSS # ------------------------- # FIXME: These cross compiler hacks should be removed for Autoconf 3.0 # # It is not sufficient to run a no-op program -- this succeeds and gives # a false negative when cross-compiling for the compute nodes on the # IBM Blue Gene/L. Instead, _AC_COMPILER_EXEEXT calls _AC_LANG_IO_PROGRAM # to create a program that writes to a file, which is sufficient to # detect cross-compiling on Blue Gene. Note also that AC_COMPUTE_INT # requires programs that create files when not cross-compiling, so it # is safe and not a bad idea to check for this capability in general. m4_define([_AC_COMPILER_EXEEXT_CROSS], [# Check that the compiler produces executables we can run. If not, either # the compiler is broken, or we cross compile. AC_MSG_CHECKING([whether we are cross compiling]) if test "$cross_compiling" != yes; then _AC_DO_VAR(ac_link) if _AC_DO_TOKENS([./conftest$ac_cv_exeext]); then cross_compiling=no else if test "$cross_compiling" = maybe; then cross_compiling=yes else AC_MSG_FAILURE([cannot run _AC_LANG compiled programs. If you meant to cross compile, use `--host'.]) fi fi fi AC_MSG_RESULT([$cross_compiling]) ])# _AC_COMPILER_EXEEXT_CROSS # _AC_COMPILER_EXEEXT_O # --------------------- # Check for the extension used when `-o foo'. Try to see if ac_cv_exeext, # as computed by _AC_COMPILER_EXEEXT_DEFAULT is OK. m4_define([_AC_COMPILER_EXEEXT_O], [AC_MSG_CHECKING([for suffix of executables]) AS_IF([_AC_DO_VAR(ac_link)], [# If both `conftest.exe' and `conftest' are `present' (well, observable) # catch `conftest.exe'. For instance with Cygwin, `ls conftest' will # work properly (i.e., refer to `conftest.exe'), while it won't with # `rm'. for ac_file in conftest.exe conftest conftest.*; do test -f "$ac_file" || continue case $ac_file in _AC_COMPILER_EXEEXT_REJECT ) ;; *.* ) ac_cv_exeext=`expr "$ac_file" : ['[^.]*\(\..*\)']` break;; * ) break;; esac done], [AC_MSG_FAILURE([cannot compute suffix of executables: cannot compile and link])]) rm -f conftest conftest$ac_cv_exeext AC_MSG_RESULT([$ac_cv_exeext]) ])# _AC_COMPILER_EXEEXT_O # _AC_COMPILER_EXEEXT # ------------------- # Check for the extension used for executables. It compiles a test # executable. If this is called, the executable extensions will be # automatically used by link commands run by the configure script. # # Note that some compilers (cross or not), strictly obey to `-o foo' while # the host requires `foo.exe', so we should not depend upon `-o' to # test EXEEXT. But then, be sure not to destroy user files. # # Must be run before _AC_COMPILER_OBJEXT because _AC_COMPILER_EXEEXT_DEFAULT # checks whether the compiler works. # # Do not rename this macro; Automake decides whether EXEEXT is used # by checking whether `_AC_COMPILER_EXEEXT' has been expanded. # # See _AC_COMPILER_EXEEXT_CROSS for why we need _AC_LANG_IO_PROGRAM. m4_define([_AC_COMPILER_EXEEXT], [AC_LANG_CONFTEST([_AC_LANG_NULL_PROGRAM]) ac_clean_files_save=$ac_clean_files ac_clean_files="$ac_clean_files a.out a.out.dSYM a.exe b.out" _AC_COMPILER_EXEEXT_DEFAULT rm -f -r a.out a.out.dSYM a.exe conftest$ac_cv_exeext b.out ac_clean_files=$ac_clean_files_save _AC_COMPILER_EXEEXT_O rm -f conftest.$ac_ext AC_SUBST([EXEEXT], [$ac_cv_exeext])dnl ac_exeext=$EXEEXT AC_LANG_CONFTEST([_AC_LANG_IO_PROGRAM]) ac_clean_files="$ac_clean_files conftest.out" _AC_COMPILER_EXEEXT_CROSS rm -f conftest.$ac_ext conftest$ac_cv_exeext conftest.out ac_clean_files=$ac_clean_files_save ])# _AC_COMPILER_EXEEXT # _AC_COMPILER_OBJEXT # ------------------- # Check the object extension used by the compiler: typically `.o' or # `.obj'. If this is called, some other behavior will change, # determined by ac_objext. # # This macro is called by AC_LANG_COMPILER, the latter being required # by the AC_COMPILE_IFELSE macros, so use _AC_COMPILE_IFELSE. And in fact, # don't, since _AC_COMPILE_IFELSE needs to know ac_objext for the `test -s' # it includes. So do it by hand. m4_define([_AC_COMPILER_OBJEXT], [AC_CACHE_CHECK([for suffix of object files], ac_cv_objext, [AC_LANG_CONFTEST([_AC_LANG_NULL_PROGRAM]) rm -f conftest.o conftest.obj AS_IF([_AC_DO_VAR(ac_compile)], [for ac_file in conftest.o conftest.obj conftest.*; do test -f "$ac_file" || continue; case $ac_file in _AC_COMPILER_OBJEXT_REJECT ) ;; *) ac_cv_objext=`expr "$ac_file" : '.*\.\(.*\)'` break;; esac done], [_AC_MSG_LOG_CONFTEST AC_MSG_FAILURE([cannot compute suffix of object files: cannot compile])]) rm -f conftest.$ac_cv_objext conftest.$ac_ext]) AC_SUBST([OBJEXT], [$ac_cv_objext])dnl ac_objext=$OBJEXT ])# _AC_COMPILER_OBJEXT ## ------------------------------- ## ## 4. Compilers' characteristics. ## ## ------------------------------- ## # AC_LANG_WERROR # -------------- # Treat warnings from the current language's preprocessor, compiler, and # linker as fatal errors. AC_DEFUN([AC_LANG_WERROR], [m4_divert_text([DEFAULTS], [ac_[]_AC_LANG_ABBREV[]_werror_flag=]) ac_[]_AC_LANG_ABBREV[]_werror_flag=yes])# AC_LANG_WERROR
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