fix tryflag() and tryldflag()

configure

@@ -130,7 +130,7 @@ stripdir () {
 tryflag () {
   echo "Checking whether compiler accepts $2 ..."
   echo "typedef int x;" > "$tmpc"
-  if $CC_AUTO $CFLAGS_AUTO $CFLAGS $CFLAGS_POST $LDFLAGS_AUTO $LDFLAGS $LDFLAGS_POST -nostdlib "$2" -o /dev/null "$tmpc" >/dev/null 2>&1 ; then
+  if $CC_AUTO $CPPFLAGS_AUTO $CPPFLAGS $CPPFLAGS_POST $CFLAGS_AUTO $CFLAGS $CFLAGS_POST "$2" -c -o /dev/null "$tmpc" >/dev/null 2>&1 ; then
     echo "  ... yes"
     eval "$1=\"\${$1} \$2\""
     eval "$1=\${$1# }"
@@ -144,7 +144,7 @@ tryflag () {
 tryldflag () {
   echo "Checking whether linker accepts $2 ..."
   echo "typedef int x;" > "$tmpc"
-  if $CC_AUTO $CPPFLAGS_AUTO $CPPFLAGS $CPPFLAGS_POST $CFLAGS_AUTO $CFLAGS $CFLAGS_POST "$2" -c -o /dev/null "$tmpc" >/dev/null 2>&1 ; then
+  if $CC_AUTO $CFLAGS_AUTO $CFLAGS $CFLAGS_POST $LDFLAGS_AUTO $LDFLAGS $LDFLAGS_POST -nostdlib "$2" -o /dev/null "$tmpc" >/dev/null 2>&1 ; then
     echo "  ... yes"
     eval "$1=\"\${$1} \$2\""
     eval "$1=\${$1# }"