More fixes

m4/flags.m4

@@ -23,9 +23,8 @@ AC_DEFUN([RDC_PROG_CC_FLAGS_IFELSE],
 
   ac_res=`eval echo '${'$as_ac_var'}'`
   AS_IF([test "${ac_res}" != "no"], [
-    CFLAGS="${CFLAGS_save} $1"
-    CXXFLAGS="${CFLAGS_save} $1"
-    OBJCFLAGS="${OBJCFLAGS_save} $1"
+    CXXFLAGS="${CXXFLAGS} $1"
+    OBJCFLAGS="${OBJCFLAGS} $1"
     $2
   ], [
     CFLAGS="${CFLAGS_save}"
@@ -38,3 +37,26 @@ AC_DEFUN([RDC_PROG_CC_WFLAGS],
     RDC_PROG_CC_FLAGS_IFELSE([-W$a])
   done
 ])
+
+AC_DEFUN([RDC_PROG_LINK_FLAGS_IFELSE],
+[AC_LANG_ASSERT(C)
+  CFLAGS_save="${CFLAGS}"
+  as_ac_var=`echo "ac_cv_prog_cc_flags_$1" | $as_tr_sh`
+  AC_CACHE_CHECK([if $CC accepts $1], [$as_ac_var], [
+    CFLAGS="${CFLAGS_save} $1"
+    AC_COMPILE_IFELSE([AC_LANG_PROGRAM()], [
+      eval "$as_ac_var=yes"
+    ],[
+      eval "$as_ac_var=no"
+    ])
+  ])
+
+  ac_res=`eval echo '${'$as_ac_var'}'`
+  AS_IF([test "${ac_res}" != "no"], [
+    true
+    $2
+  ], [
+    LDFLAGS="${CFLAGS_save}"
+    $3
+  ])
+])