RFR (XS) 8233698: GCC 4.8.5 build failure after JDK-8233530

[Aleksey Shipilev]

Bug:
  https://bugs.openjdk.java.net/browse/JDK-8233698

Our current RHEL-based CIs fail to compile jdk/jdk. That C++14 compat is the gift that keeps on
giving! The fix is to get even deeper into the warning disabling story:

diff -r bb2a436e616c src/hotspot/share/memory/operator_new.cpp
--- a/src/hotspot/share/memory/operator_new.cpp Wed Nov 06 13:43:25 2019 +0800
+++ b/src/hotspot/share/memory/operator_new.cpp Wed Nov 06 12:31:23 2019 +0100
@@ -89,11 +89,13 @@
   fatal("Should not call global delete []");
 }

 #ifdef __GNUG__
 // Warning disabled for gcc 5.4
+// Warning for unknown warning disabled for gcc 4.8.5
 PRAGMA_DIAG_PUSH
+PRAGMA_DISABLE_GCC_WARNING("-Wpragmas")
 PRAGMA_DISABLE_GCC_WARNING("-Wc++14-compat")
 #endif // __GNUG__

 void operator delete(void* p, size_t size) throw() {
   fatal("Should not call global sized delete");

Testing: gcc 4.8.5 build

-- 
Thanks,
-Aleksey