Edit: /usr/share/aclocal-1.16/prog-cc-c-o.m4 (1691B)
## -*- Autoconf -*-
# Copyright (C) 1999-2018 Free Software Foundation, Inc.
#
# This file is free software; the Free Software Foundation
# gives unlimited permission to copy and/or distribute it,
# with or without modifications, as long as this notice is preserved.
# _AM_PROG_CC_C_O
# ---------------
# Like AC_PROG_CC_C_O, but changed for automake. We rewrite AC_PROG_CC
# to automatically call this.
AC_DEFUN([_AM_PROG_CC_C_O],
[AC_REQUIRE([AM_AUX_DIR_EXPAND])dnl
AC_REQUIRE_AUX_FILE([compile])dnl
AC_LANG_PUSH([C])dnl
AC_CACHE_CHECK(
[whether $CC understands -c and -o together],
[am_cv_prog_cc_c_o],
[AC_LANG_CONFTEST([AC_LANG_PROGRAM([])])
# Make sure it works both with $CC and with simple cc.
# Following AC_PROG_CC_C_O, we do the test twice because some
# compilers refuse to overwrite an existing .o file with -o,
# though they will create one.
am_cv_prog_cc_c_o=yes
for am_i in 1 2; do
if AM_RUN_LOG([$CC -c conftest.$ac_ext -o conftest2.$ac_objext]) \
&& test -f conftest2.$ac_objext; then
: OK
else
am_cv_prog_cc_c_o=no
break
fi
done
rm -f core conftest*
unset am_i])
if test "$am_cv_prog_cc_c_o" != yes; then
# Losing compiler, so override with the script.
# FIXME: It is wrong to rewrite CC.
# But if we don't then we get into trouble of one sort or another.
# A longer-term fix would be to have automake use am__CC in this case,
# and then we could set am__CC="\$(top_srcdir)/compile \$(CC)"
CC="$am_aux_dir/compile $CC"
fi
AC_LANG_POP([C])])
# For backward compatibility.
AC_DEFUN_ONCE([AM_PROG_CC_C_O], [AC_REQUIRE([AC_PROG_CC])])