OpenJDK11 build on macOS with autoconf 2.72 / -std=gnu++11 option

[Baesken, Matthias]

Seems there is already an util helper   " UTIL_GET_NON_MATCHING_VALUES"  .
So should we do something like this  (maybe with a few more unwanted  -std= settings ?  
Seems the  UTIL_GET_NON_MATCHING_VALUES  so far accepts  only fix strings, is that correct ?


diff --git a/make/autoconf/toolchain.m4 b/make/autoconf/toolchain.m4
index 289eec3356b..8ff95c1114c 100644
--- a/make/autoconf/toolchain.m4
+++ b/make/autoconf/toolchain.m4
@@ -389,6 +389,12 @@ AC_DEFUN_ONCE([TOOLCHAIN_POST_DETECTION],
   # This is necessary since AC_PROG_CC defaults CFLAGS to "-g -O2"
   CFLAGS="$ORG_CFLAGS"
   CXXFLAGS="$ORG_CXXFLAGS"
+
+  # filter out some unwanted additions autoconf may add to CXX; we saw this on macOS with autoconf 2.72
+  UTIL_GET_NON_MATCHING_VALUES(cxx_filtered, $CXX, -std=c++11 -std=gnu++11)
+  if test "x$cxx_filtered" != x; then
+    CXX="$cxx_filtered"
+  fi
 ])


Best regards, Matthias

>
>Btw. Is there already something  at make/autoconf that does similar filtering of unwanted flags ?
>The mentioned TOOLCHAIN_POST_DETECTION  seems just to reset some variables  like CXX_CFLAGS to old values ,  not sure if  this is what we want here ?
>
>
>>Hi Erik, I created  :
>>
>>https://bugs.openjdk.org/browse/JDK-8323008
>>8323008: filter out any -std* flags added by autoconf from CC/CXX
>>