`-belf' test

[Golubev I. N.]

Version: 1.4

It is just a fore- port of patch in <address@hidden> to
libtool-1.4 and autoconf-2.50.

Unnecessary `-belf' passed to compiler always causes warnings and
sometimes causes badly- reproducible wrong code generation.  The patch
tries to avoid this.

It still assumes that, regardless of whether our target is native or
cross, our `file' program recognizes ELF files.  I do not know more
portable way to check that we have created an ELF object.  E. g.,
`head -c 4' is not as portable as `tail +16c' (otherwise we could just
`echo' right magic and `cmp' it with beginning of the object).

--- libtool.m4  2001/06/14 14:10:54     1.5
+++ libtool.m4  2001/06/30 17:03:20     1.7
@@ -99,16 +99,24 @@
 
 *-*-sco3.2v5*)
   # On SCO OpenServer 5, we need -belf to get full-featured binaries.
-  SAVE_CFLAGS="$CFLAGS"
-  CFLAGS="$CFLAGS -belf"
   AC_CACHE_CHECK([whether the C compiler needs -belf], lt_cv_cc_needs_belf,
-    [AC_LANG_SAVE
-     AC_LANG_C
-     AC_TRY_LINK([],[],[lt_cv_cc_needs_belf=yes],[lt_cv_cc_needs_belf=no])
-     AC_LANG_RESTORE])
-  if test x"$lt_cv_cc_needs_belf" != x"yes"; then
-    # this is probably gcc 2.8.0, egcs 1.0 or newer; no need for -belf
+[  AC_LIBTOOL_SCO5_ELF
+  if test x"$lt_have_elf_compiler" != xyes; then
+  dnl to prevent adding -belf twice
+    SAVE_CFLAGS="$CFLAGS"
+    CFLAGS="$CFLAGS -belf"
+    AC_LIBTOOL_SCO5_ELF
+    if test x"$lt_have_elf_compiler" != xyes; then
+      lt_cv_cc_needs_belf=yes
+    else
+      AC_MSG_ERROR([can not make your compiler ($CC $SAVE_CFLAGS $LDFLAGS) 
generate full-featured ELF objects])
+    fi
     CFLAGS="$SAVE_CFLAGS"
+  else
+    lt_cv_cc_needs_belf=no
+  fi])
+  if test x"$lt_cv_cc_needs_belf" = yes; then
+    CFLAGS="$CFLAGS -belf"
   fi
   ;;
 
@@ -3422,6 +3430,24 @@
     LIBLTDL="-lltdl"
     INCLTDL=
   fi
+])
+dnl checks that current compiler setup generates ELF objects
+AC_DEFUN(AC_LIBTOOL_SCO5_ELF, [dnl
+AC_REQUIRE([AC_PROG_CC])dnl
+lt_have_elf_compiler=no
+cat > conftest.$ac_ext <<EOF
+[#]line __oline__ "configure"
+struct dummy;
+EOF
+if AC_TRY_EVAL(ac_compile) && test -s conftest.o; then
+  if file conftest.o|fgrep ELF>/dev/null; then
+    lt_have_elf_compiler=yes
+  fi
+else
+  echo "$as_me: failed program was:" >&AS_MESSAGE_LOG_FD
+  cat conftest.$ac_ext >&AS_MESSAGE_LOG_FD
+fi
+rm -f conftest*
 ])
 
 # old names