dnl See whether we need a declaration for a function.
dnl The result is highly dependent on the INCLUDES passed in, so make sure
dnl to use a different cache variable name in this macro if it is invoked
dnl in a different context somewhere else.
dnl gcc_AC_CHECK_DECL(SYMBOL,
dnl 	[ACTION-IF-FOUND [, ACTION-IF-NOT-FOUND [, INCLUDES]]])
AC_DEFUN([gcc_AC_CHECK_DECL],
[AC_MSG_CHECKING([whether $1 is declared])
AC_CACHE_VAL(gcc_cv_have_decl_$1,
[AC_TRY_COMPILE([$4],
[#ifndef $1
char *(*pfn) = (char *(*)) $1 ;
#endif], eval "gcc_cv_have_decl_$1=yes", eval "gcc_cv_have_decl_$1=no")])
if eval "test \"`echo '$gcc_cv_have_decl_'$1`\" = yes"; then
  AC_MSG_RESULT(yes) ; ifelse([$2], , :, [$2])
else
  AC_MSG_RESULT(no) ; ifelse([$3], , :, [$3])
fi
])dnl

dnl Check multiple functions to see whether each needs a declaration.
dnl Arrange to define HAVE_DECL_<FUNCTION> to 0 or 1 as appropriate.
dnl gcc_AC_CHECK_DECLS(SYMBOLS,
dnl 	[ACTION-IF-NEEDED [, ACTION-IF-NOT-NEEDED [, INCLUDES]]])
AC_DEFUN([gcc_AC_CHECK_DECLS],
[for ac_func in $1
do
changequote(, )dnl
  ac_tr_decl=HAVE_DECL_`echo $ac_func | tr 'abcdefghijklmnopqrstuvwxyz' 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'`
changequote([, ])dnl
gcc_AC_CHECK_DECL($ac_func,
  [AC_DEFINE_UNQUOTED($ac_tr_decl, 1) $2],
  [AC_DEFINE_UNQUOTED($ac_tr_decl, 0) $3],
dnl It is possible that the include files passed in here are local headers
dnl which supply a backup declaration for the relevant prototype based on
dnl the definition of (or lack of) the HAVE_DECL_ macro.  If so, this test
dnl will always return success.  E.g. see libiberty.h's handling of
dnl `basename'.  To avoid this, we define the relevant HAVE_DECL_ macro to
dnl 1 so that any local headers used do not provide their own prototype
dnl during this test.
#undef $ac_tr_decl
#define $ac_tr_decl 1
  $4
)
done
dnl Automatically generate config.h entries via autoheader.
if test x = y ; then
  patsubst(translit([$1], [a-z], [A-Z]), [\w+],
    [AC_DEFINE([HAVE_DECL_\&], 1,
      [Define to 1 if we found this declaration otherwise define to 0.])])dnl
fi
])