autoconf/ast_gcc_attribute.m4

   1 # Helper function to check for gcc attributes.
   2 # AST_GCC_ATTRIBUTE([attribute name], [attribute syntax], [attribute scope], [makeopts flag])
   3
   4 AC_DEFUN([AST_GCC_ATTRIBUTE],
   5 [
   6 AC_MSG_CHECKING(for compiler 'attribute $1' support)
   7 saved_CFLAGS="$CFLAGS"
   8 CFLAGS="$CFLAGS -Wall -Wno-unused -Werror"
   9 m4_ifval([$4],$4=0)
  10 ax_cv_have_func_attribute_$1=0
  11
  12 AC_COMPILE_IFELSE(
  13         [AC_LANG_PROGRAM(
  14                 m4_ifval([$2],
  15                         [$3 void __attribute__(($2)) *test(void *muffin, ...) ;],
  16                         [$3 void __attribute__(($1)) *test(void *muffin, ...) {return (void *) 0;}]))],
  17         AC_MSG_RESULT(yes)
  18         m4_ifval([$4],$4=1)
  19         ax_cv_have_func_attribute_$1=1
  20         AC_DEFINE_UNQUOTED([HAVE_ATTRIBUTE_$1], 1, [Define to 1 if your GCC C compiler supports the '$1' attribute.]),
  21         AC_MSG_RESULT(no)
  22 )
  23
  24 m4_ifval([$4],[AC_SUBST($4)])
  25 CFLAGS="$saved_CFLAGS"
  26 ]
  27 )