tools/missing-macros/src/m4/as-compiler-flag.m4

   1 dnl as-compiler-flag.m4 0.1.0
   2
   3 dnl autostars m4 macro for detection of compiler flags
   4
   5 dnl David Schleef <ds@schleef.org>
   6
   7 dnl $Id: as-compiler-flag.m4,v 1.1 2005/12/15 23:35:19 ds Exp $
   8
   9 dnl AS_COMPILER_FLAG(CFLAGS, ACTION-IF-ACCEPTED, [ACTION-IF-NOT-ACCEPTED])
  10 dnl Tries to compile with the given CFLAGS.
  11 dnl Runs ACTION-IF-ACCEPTED if the compiler can compile with the flags,
  12 dnl and ACTION-IF-NOT-ACCEPTED otherwise.
  13
  14 AC_DEFUN([AS_COMPILER_FLAG],
  15 [
  16   AC_MSG_CHECKING([to see if compiler understands $1])
  17
  18   save_CFLAGS="$CFLAGS"
  19   CFLAGS="$CFLAGS $1"
  20
  21   AC_TRY_COMPILE([ ], [], [flag_ok=yes], [flag_ok=no])
  22   CFLAGS="$save_CFLAGS"
  23
  24   if test "X$flag_ok" = Xyes ; then
  25     m4_ifvaln([$2],[$2])
  26     true
  27   else
  28     m4_ifvaln([$3],[$3])
  29     true
  30   fi
  31   AC_MSG_RESULT([$flag_ok])
  32 ])
  33
  34 dnl AS_COMPILER_FLAGS(VAR, FLAGS)
  35 dnl Tries to compile with the given CFLAGS.
  36
  37 AC_DEFUN([AS_COMPILER_FLAGS],
  38 [
  39   list=$2
  40   flags_supported=""
  41   flags_unsupported=""
  42   AC_MSG_CHECKING([for supported compiler flags])
  43   for each in $list
  44   do
  45     save_CFLAGS="$CFLAGS"
  46     CFLAGS="$CFLAGS $each"
  47     AC_TRY_COMPILE([ ], [], [flag_ok=yes], [flag_ok=no])
  48     CFLAGS="$save_CFLAGS"
  49
  50     if test "X$flag_ok" = Xyes ; then
  51       flags_supported="$flags_supported $each"
  52     else
  53       flags_unsupported="$flags_unsupported $each"
  54     fi
  55   done
  56   AC_MSG_RESULT([$flags_supported])
  57   if test "X$flags_unsupported" != X ; then
  58     AC_MSG_WARN([unsupported compiler flags: $flags_unsupported])
  59   fi
  60   $1="$$1 $flags_supported"
  61 ])
  62