c.m4

autoconf是一个产生可以自动配置源代码包

# Set ac_cpp_err to a non-empty value if the preprocessor failed.
# This macro is for all languages, not only C.
AC_DEFUN([_AC_PROG_PREPROC_WORKS_IFELSE],
[ac_preproc_ok=false
for ac_[]_AC_LANG_ABBREV[]_preproc_warn_flag in '' yes
do
  # Use a header file that comes with gcc, so configuring glibc
  # with a fresh cross-compiler works.
  # Prefer <limits.h> to <assert.h> if __STDC__ is defined, since
  # <limits.h> exists even on freestanding compilers.
  # On the NeXT, cc -E runs the code through the compiler's parser,
  # not just through cpp. "Syntax error" is here to catch this case.
  _AC_PREPROC_IFELSE([AC_LANG_SOURCE([[@%:@ifdef __STDC__
@%:@ include <limits.h>
@%:@else
@%:@ include <assert.h>
@%:@endif
		     Syntax error]])],
		     [],
		     [# Broken: fails on valid input.
continue])

  # OK, works on sane cases.  Now check whether nonexistent headers
  # can be detected and how.
  _AC_PREPROC_IFELSE([AC_LANG_SOURCE([[@%:@include <ac_nonexistent.h>]])],
		     [# Broken: success on invalid input.
continue],
		     [# Passes both tests.
ac_preproc_ok=:
break])

done
# Because of `break', _AC_PREPROC_IFELSE's cleaning code was skipped.
rm -f conftest.err conftest.$ac_ext
AS_IF([$ac_preproc_ok], [$1], [$2])])# _AC_PROG_PREPROC_WORKS_IFELSE


# AC_PROG_CPP
# -----------
# Find a working C preprocessor.
# We shouldn't have to require AC_PROG_CC, but this is due to the concurrency
# between the AC_LANG_COMPILER_REQUIRE family and that of AC_PROG_CC.
AN_MAKEVAR([CPP], [AC_PROG_CPP])
AN_PROGRAM([cpp], [AC_PROG_CPP])
AC_DEFUN([AC_PROG_CPP],
[AC_REQUIRE([AC_PROG_CC])dnl
AC_ARG_VAR([CPP],      [C preprocessor])dnl
_AC_ARG_VAR_CPPFLAGS()dnl
AC_LANG_PUSH(C)dnl
AC_MSG_CHECKING([how to run the C preprocessor])
# On Suns, sometimes $CPP names a directory.
if test -n "$CPP" && test -d "$CPP"; then
  CPP=
fi
if test -z "$CPP"; then
  AC_CACHE_VAL([ac_cv_prog_CPP],
  [dnl
    # Double quotes because CPP needs to be expanded
    for CPP in "$CC -E" "$CC -E -traditional-cpp" "/lib/cpp"
    do
      _AC_PROG_PREPROC_WORKS_IFELSE([break])
    done
    ac_cv_prog_CPP=$CPP
  ])dnl
  CPP=$ac_cv_prog_CPP
else
  ac_cv_prog_CPP=$CPP
fi
AC_MSG_RESULT([$CPP])
_AC_PROG_PREPROC_WORKS_IFELSE([],
		[AC_MSG_FAILURE([C preprocessor "$CPP" fails sanity check])])
AC_SUBST(CPP)dnl
AC_LANG_POP(C)dnl
])# AC_PROG_CPP

# AC_PROG_CPP_WERROR
# ------------------
# Treat warnings from the preprocessor as errors.
AC_DEFUN([AC_PROG_CPP_WERROR],
[AC_REQUIRE([AC_PROG_CPP])dnl
ac_c_preproc_warn_flag=yes])# AC_PROG_CPP_WERROR

# AC_LANG_COMPILER(C)
# -------------------
# Find the C compiler.  Must be AC_DEFUN'd to be AC_REQUIRE'able.
AC_DEFUN([AC_LANG_COMPILER(C)],
[AC_REQUIRE([AC_PROG_CC])])


# ac_cv_prog_gcc
# --------------
# We used to name the cache variable this way.
AU_DEFUN([ac_cv_prog_gcc],
[ac_cv_c_compiler_gnu])


# AC_PROG_CC([COMPILER ...])
# --------------------------
# COMPILER ... is a space separated list of C compilers to search for.
# This just gives the user an opportunity to specify an alternative
# search list for the C compiler.
AN_MAKEVAR([CC],  [AC_PROG_CC])
AN_PROGRAM([cc],  [AC_PROG_CC])
AN_PROGRAM([gcc], [AC_PROG_CC])
AC_DEFUN([AC_PROG_CC],
[AC_LANG_PUSH(C)dnl
AC_ARG_VAR([CC],     [C compiler command])dnl
AC_ARG_VAR([CFLAGS], [C compiler flags])dnl
_AC_ARG_VAR_LDFLAGS()dnl
_AC_ARG_VAR_CPPFLAGS()dnl
m4_ifval([$1],
      [AC_CHECK_TOOLS(CC, [$1])],
[AC_CHECK_TOOL(CC, gcc)
if test -z "$CC"; then
  dnl Here we want:
  dnl	AC_CHECK_TOOL(CC, cc)
  dnl but without the check for a tool without the prefix.
  dnl Until the check is removed from there, copy the code:
  if test -n "$ac_tool_prefix"; then
    AC_CHECK_PROG(CC, [${ac_tool_prefix}cc], [${ac_tool_prefix}cc])
  fi
fi
if test -z "$CC"; then
  AC_CHECK_PROG(CC, cc, cc, , , /usr/ucb/cc)
fi
if test -z "$CC"; then
  AC_CHECK_TOOLS(CC, cl.exe)
fi
])

test -z "$CC" && AC_MSG_FAILURE([no acceptable C compiler found in \$PATH])

# Provide some information about the compiler.
_AS_ECHO_LOG([checking for _AC_LANG compiler version])
ac_compiler=`set X $ac_compile; echo $[2]`
_AC_DO([$ac_compiler --version >&AS_MESSAGE_LOG_FD])
_AC_DO([$ac_compiler -v >&AS_MESSAGE_LOG_FD])
_AC_DO([$ac_compiler -V >&AS_MESSAGE_LOG_FD])

m4_expand_once([_AC_COMPILER_EXEEXT])[]dnl
m4_expand_once([_AC_COMPILER_OBJEXT])[]dnl
_AC_LANG_COMPILER_GNU
GCC=`test $ac_compiler_gnu = yes && echo yes`
_AC_PROG_CC_G
_AC_PROG_CC_C89
AC_LANG_POP(C)dnl
])# AC_PROG_CC


# _AC_PROG_CC_G
# -------------
# Check whether -g works, even if CFLAGS is set, in case the package
# plays around with CFLAGS (such as to build both debugging and normal
# versions of a library), tasteless as that idea is.
# Don't consider -g to work if it generates warnings when plain compiles don't.
m4_define([_AC_PROG_CC_G],
[ac_test_CFLAGS=${CFLAGS+set}
ac_save_CFLAGS=$CFLAGS
AC_CACHE_CHECK(whether $CC accepts -g, ac_cv_prog_cc_g,
  [ac_save_c_werror_flag=$ac_c_werror_flag
   ac_c_werror_flag=yes
   ac_cv_prog_cc_g=no
   CFLAGS="-g"
   _AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
     [ac_cv_prog_cc_g=yes],
     [CFLAGS=""
      _AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
	[],
	[ac_c_werror_flag=$ac_save_c_werror_flag
	 CFLAGS="-g"
	 _AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
	   [ac_cv_prog_cc_g=yes])])])
   ac_c_werror_flag=$ac_save_c_werror_flag])
if test "$ac_test_CFLAGS" = set; then
  CFLAGS=$ac_save_CFLAGS
elif test $ac_cv_prog_cc_g = yes; then
  if test "$GCC" = yes; then
    CFLAGS="-g -O2"
  else
    CFLAGS="-g"
  fi
else
  if test "$GCC" = yes; then
    CFLAGS="-O2"
  else
    CFLAGS=
  fi
fi[]dnl
])# _AC_PROG_CC_G


# AC_PROG_GCC_TRADITIONAL
# -----------------------
AN_FUNCTION([ioctl],   [AC_PROG_GCC_TRADITIONAL])
AC_DEFUN([AC_PROG_GCC_TRADITIONAL],
[if test $ac_cv_c_compiler_gnu = yes; then
    AC_CACHE_CHECK(whether $CC needs -traditional,
      ac_cv_prog_gcc_traditional,
[  ac_pattern="Autoconf.*'x'"
  AC_EGREP_CPP($ac_pattern, [#include <sgtty.h>
Autoconf TIOCGETP],
  ac_cv_prog_gcc_traditional=yes, ac_cv_prog_gcc_traditional=no)

  if test $ac_cv_prog_gcc_traditional = no; then
    AC_EGREP_CPP($ac_pattern, [#include <termio.h>
Autoconf TCGETA],
    ac_cv_prog_gcc_traditional=yes)
  fi])
  if test $ac_cv_prog_gcc_traditional = yes; then
    CC="$CC -traditional"
  fi
fi
])# AC_PROG_GCC_TRADITIONAL


# AC_PROG_CC_C_O
# --------------
AC_DEFUN([AC_PROG_CC_C_O],
[AC_REQUIRE([AC_PROG_CC])dnl
if test "x$CC" != xcc; then
  AC_MSG_CHECKING([whether $CC and cc understand -c and -o together])
else
  AC_MSG_CHECKING([whether cc understands -c and -o together])
fi
set dummy $CC; ac_cc=`echo $[2] |
		      sed 's/[[^a-zA-Z0-9_]]/_/g;s/^[[0-9]]/_/'`
AC_CACHE_VAL(ac_cv_prog_cc_${ac_cc}_c_o,
[AC_LANG_CONFTEST([AC_LANG_PROGRAM([])])
# Make sure it works both with $CC and with simple cc.
# We do the test twice because some compilers refuse to overwrite an
# existing .o file with -o, though they will create one.
ac_try='$CC -c conftest.$ac_ext -o conftest2.$ac_objext >&AS_MESSAGE_LOG_FD'
rm -f conftest2.*
if _AC_DO_VAR(ac_try) &&
   test -f conftest2.$ac_objext && _AC_DO_VAR(ac_try);
then
  eval ac_cv_prog_cc_${ac_cc}_c_o=yes
  if test "x$CC" != xcc; then
    # Test first that cc exists at all.
    if _AC_DO_TOKENS(cc -c conftest.$ac_ext >&AS_MESSAGE_LOG_FD); then
      ac_try='cc -c conftest.$ac_ext -o conftest2.$ac_objext >&AS_MESSAGE_LOG_FD'
      rm -f conftest2.*
      if _AC_DO_VAR(ac_try) &&
	 test -f conftest2.$ac_objext && _AC_DO_VAR(ac_try);
      then
	# cc works too.
	:
      else
	# cc exists but doesn't like -o.
	eval ac_cv_prog_cc_${ac_cc}_c_o=no
      fi
    fi
  fi
else
  eval ac_cv_prog_cc_${ac_cc}_c_o=no
fi
rm -f core conftest*
])dnl
if eval test \$ac_cv_prog_cc_${ac_cc}_c_o = yes; then
  AC_MSG_RESULT([yes])
else
  AC_MSG_RESULT([no])
  AC_DEFINE(NO_MINUS_C_MINUS_O, 1,
	   [Define to 1 if your C compiler doesn't accept -c and -o together.])
fi
])# AC_PROG_CC_C_O


# ---------------------- #
# 3c. The C++ compiler.  #
# ---------------------- #


# AC_LANG_PREPROC(C++)
# ---------------------
# Find the C++ preprocessor.  Must be AC_DEFUN'd to be AC_REQUIRE'able.
AC_DEFUN([AC_LANG_PREPROC(C++)],
[AC_REQUIRE([AC_PROG_CXXCPP])])


# AC_PROG_CXXCPP
# --------------
# Find a working C++ preprocessor.
# We shouldn't have to require AC_PROG_CC, but this is due to the concurrency
# between the AC_LANG_COMPILER_REQUIRE family and that of AC_PROG_CXX.
AC_DEFUN([AC_PROG_CXXCPP],
[AC_REQUIRE([AC_PROG_CXX])dnl
AC_ARG_VAR([CXXCPP],   [C++ preprocessor])dnl
_AC_ARG_VAR_CPPFLAGS()dnl
AC_LANG_PUSH(C++)dnl
AC_MSG_CHECKING([how to run the C++ preprocessor])
if test -z "$CXXCPP"; then
  AC_CACHE_VAL(ac_cv_prog_CXXCPP,
  [dnl
    # Double quotes because CXXCPP needs to be expanded
    for CXXCPP in "$CXX -E" "/lib/cpp"
    do
      _AC_PROG_PREPROC_WORKS_IFELSE([break])
    done
    ac_cv_prog_CXXCPP=$CXXCPP
  ])dnl
  CXXCPP=$ac_cv_prog_CXXCPP
else
  ac_cv_prog_CXXCPP=$CXXCPP
fi
AC_MSG_RESULT([$CXXCPP])
_AC_PROG_PREPROC_WORKS_IFELSE([],
	  [AC_MSG_FAILURE([C++ preprocessor "$CXXCPP" fails sanity check])])
AC_SUBST(CXXCPP)dnl
AC_LANG_POP(C++)dnl
])# AC_PROG_CXXCPP


# AC_LANG_COMPILER(C++)
# ---------------------
# Find the C++ compiler.  Must be AC_DEFUN'd to be AC_REQUIRE'able.
AC_DEFUN([AC_LANG_COMPILER(C++)],
[AC_REQUIRE([AC_PROG_CXX])])


# ac_cv_prog_gxx
# --------------
# We used to name the cache variable this way.
AU_DEFUN([ac_cv_prog_gxx],
[ac_cv_cxx_compiler_gnu])


# AC_PROG_CXX([LIST-OF-COMPILERS])
# --------------------------------
# LIST-OF-COMPILERS is a space separated list of C++ compilers to search
# for (if not specified, a default list is used).  This just gives the
# user an opportunity to specify an alternative search list for the C++
# compiler.
# aCC	HP-UX C++ compiler much better than `CC', so test before.
# FCC   Fujitsu C++ compiler
# KCC	KAI C++ compiler
# RCC	Rational C++
# xlC_r	AIX C Set++ (with support for reentrant code)
# xlC	AIX C Set++
AN_MAKEVAR([CXX],  [AC_PROG_CXX])
AN_PROGRAM([CC],   [AC_PROG_CXX])
AN_PROGRAM([c++],  [AC_PROG_CXX])
AN_PROGRAM([g++],  [AC_PROG_CXX])
AC_DEFUN([AC_PROG_CXX],
[AC_LANG_PUSH(C++)dnl
AC_ARG_VAR([CXX],      [C++ compiler command])dnl
AC_ARG_VAR([CXXFLAGS], [C++ compiler flags])dnl
_AC_ARG_VAR_LDFLAGS()dnl
_AC_ARG_VAR_CPPFLAGS()dnl
_AC_ARG_VAR_PRECIOUS([CCC])dnl
if test -z "$CXX"; then
  if test -n "$CCC"; then
    CXX=$CCC
  else
    AC_CHECK_TOOLS(CXX,
		   [m4_default([$1],
			       [g++ c++ gpp aCC CC cxx cc++ cl.exe FCC KCC RCC xlC_r xlC])],
		   g++)
  fi
fi
# Provide some information about the compiler.
_AS_ECHO_LOG([checking for _AC_LANG compiler version])
ac_compiler=`set X $ac_compile; echo $[2]`
_AC_DO([$ac_compiler --version >&AS_MESSAGE_LOG_FD])
_AC_DO([$ac_compiler -v >&AS_MESSAGE_LOG_FD])
_AC_DO([$ac_compiler -V >&AS_MESSAGE_LOG_FD])

m4_expand_once([_AC_COMPILER_EXEEXT])[]dnl
m4_expand_once([_AC_COMPILER_OBJEXT])[]dnl
_AC_LANG_COMPILER_GNU
GXX=`test $ac_compiler_gnu = yes && echo yes`
_AC_PROG_CXX_G
AC_LANG_POP(C++)dnl
])# AC_PROG_CXX


# _AC_PROG_CXX_G
# --------------
# Check whether -g works, even if CXXFLAGS is set, in case the package
# plays around with CXXFLAGS (such as to build both debugging and
# normal versions of a library), tasteless as that idea is.
# Don't consider -g to work if it generates warnings when plain compiles don't.
m4_define([_AC_PROG_CXX_G],
[ac_test_CXXFLAGS=${CXXFLAGS+set}
ac_save_CXXFLAGS=$CXXFLAGS
AC_CACHE_CHECK(whether $CXX accepts -g, ac_cv_prog_cxx_g,
  [ac_save_cxx_werror_flag=$ac_cxx_werror_flag
   ac_cxx_werror_flag=yes
   ac_cv_prog_cxx_g=no
   CXXFLAGS="-g"
   _AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
     [ac_cv_prog_cxx_g=yes],
     [CXXFLAGS=""
      _AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
	[],
	[ac_cxx_werror_flag=$ac_save_cxx_werror_flag
	 CXXFLAGS="-g"
	 _AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
	   [ac_cv_prog_cxx_g=yes])])])
   ac_cxx_werror_flag=$ac_save_cxx_werror_flag])
if test "$ac_test_CXXFLAGS" = set; then
  CXXFLAGS=$ac_save_CXXFLAGS
elif test $ac_cv_prog_cxx_g = yes; then
  if test "$GXX" = yes; then
    CXXFLAGS="-g -O2"
  else
    CXXFLAGS="-g"
  fi
else
  if test "$GXX" = yes; then