build-sys: use $LIBS rather than LDFLAGS

Fixes: https://github.com/karelzak/util-linux/pull/1349
Signed-off-by: Karel Zak <kzak@redhat.com>

configure.ac

@@ -843,7 +843,7 @@ char *c = crypt("abc","pw");
   have_libcrypt=no
   have_crypt=yes
 ],[
-  UL_SET_FLAGS([], [], [-lcrypt])
+  UL_SET_LIBS([-lcrypt])
   AC_LINK_IFELSE([AC_LANG_PROGRAM([[
   #ifdef HAVE_CRYPT_H
   #include <crypt.h>
@@ -859,7 +859,7 @@ char *c = crypt("abc","pw");
   ],[
   AC_MSG_WARN([crypt() is not available])
   ])
-  UL_RESTORE_FLAGS
+  UL_RESTORE_LIBS
 ])
 AM_CONDITIONAL([HAVE_LIBCRYPT], [test "x$have_libcrypt" = xyes])
 
@@ -881,10 +881,10 @@ AS_IF([test "x$with_selinux" = xno], [
     UL_PKG_STATIC([SELINUX_LIBS_STATIC], [libselinux])
     AM_CONDITIONAL([HAVE_SELINUX], [true])
 
-    UL_SET_FLAGS([], [], [$SELINUX_LIBS])
+    UL_SET_LIBS([$SELINUX_LIBS])
     # This function is missing in old libselinux 1.xx versions
     AC_CHECK_FUNCS([security_get_initial_context])
-    UL_RESTORE_FLAGS
+    UL_RESTORE_LIBS
   ])
 ])
 AC_SUBST([SELINUX_LIBS])

m4/ul.m4

@@ -67,28 +67,21 @@ AC_DEFUN([UL_SET_ARCH], [
 ])
 
 
-dnl UL_SET_FLAGS(CFLAGS, CPPFLAGS, LDFLAGS)
+dnl UL_SET_LIBS(LIBS)
 dnl
-dnl Sets new global CFLAGS, CPPFLAGS and LDFLAG, the original
-dnl setting could be restored by UL_RESTORE_FLAGS()
+dnl Sets new global LIBS, the original setting could be restored by UL_RESTORE_LIBS()
 dnl
-AC_DEFUN([UL_SET_FLAGS], [
-  old_CFLAGS="$CFLAGS"
-  old_CPPFLAGS="$CPPFLAGS"
-  old_LDFLAGS="$LDFLAGS"
-  CFLAGS="$CFLAGS $1"
-  CPPFLAGS="$CPPFLAGS $2"
-  LDFLAGS="$LDFLAGS $3"
+AC_DEFUN([UL_SET_LIBS], [
+  old_LIBS="$LIBS"
+  LIBS="$LIBS $1"
 ])
 
-dnl UL_RESTORE_FLAGS()
+dnl UL_RESTORE_LIBS()
 dnl
-dnl Restores CFLAGS, CPPFLAGS and LDFLAG previously saved by UL_SET_FLAGS()
+dnl Restores LIBS previously saved by UL_SET_LIBS()
 dnl
-AC_DEFUN([UL_RESTORE_FLAGS], [
-  CFLAGS="$old_CFLAGS"
-  CPPFLAGS="$old_CPPFLAGS"
-  LDFLAGS="$old_LDFLAGS"
+AC_DEFUN([UL_RESTORE_LIBS], [
+  LIBS="$old_LIBS"
 ])