cln_mirror/m4/as-underscore.m4

dnl -*- Autoconf -*-
dnl Copyright (C) 1993-2003 Free Software Foundation, Inc.
dnl This file is free software, distributed under the terms of the GNU
dnl General Public License.  As a special exception to the GNU General
dnl Public License, this file may be distributed as part of a program
dnl that contains a configuration script generated by Autoconf, under
dnl the same distribution terms as the rest of that program.

dnl From Bruno Haible, Marcus Daniels, Sam Steingold.

AC_PREREQ(2.57)

AC_DEFUN([CL_AS_UNDERSCORE],
[AC_BEFORE([$0], [CL_GLOBAL_CONSTRUCTORS])
m4_pattern_allow([^AS_UNDERSCORE$])
AC_CACHE_CHECK(for underscore in external names, cl_cv_prog_as_underscore, [
cat > conftest.c <<EOF
#ifdef __cplusplus
extern "C"
#endif
int foo() { return 0; }
EOF
# look for the assembly language name in the .s file
AC_TRY_COMMAND(${CC-cc} -S conftest.c) >/dev/null 2>&1
if grep _foo conftest.s >/dev/null ; then
  cl_cv_prog_as_underscore=yes
else
  cl_cv_prog_as_underscore=no
fi
rm -f conftest*
])
if test $cl_cv_prog_as_underscore = yes; then
  AS_UNDERSCORE=true
  AC_DEFINE(ASM_UNDERSCORE,,[symbols are prefixed by an underscore in assembly language])
else
  AS_UNDERSCORE=false
fi
AC_SUBST(AS_UNDERSCORE)dnl
])