RFR [jdk11]: 8232084: HotSpot build failed with GCC 9.2.1

[Baesken, Matthias]

Hello,  I  please review the backport of  8232084  to jdk11 .
This is needed to make  jdk11  buildable with gcc-9   (tested on linux  x86_64) .

Changes in the jdk11 backport  compared to jdk/jdk :

hotspot/cpu/x86/macroAssembler_x86.hpp  change is not needed in jdk11
src/hotspot/share/utilities/compilerWarnings_gcc.hpp   does not exist in jdk11 so the  compilerWarnings_gcc.hpp change  goes to  compilerWarnings.hpp
additionally to be able to build with gcc-9   in make/autoconf/flags-cflags.m4  -Wno-stringop-truncation  has to be set (issues in jvmti test coding and liblcms )


(tested to build jdk11u-dev on linux x86_64  with gcc-4.8 and gcc-7 this still works too )


Bug/webrev :

https://bugs.openjdk.java.net/browse/JDK-8232084

http://cr.openjdk.java.net/~mbaesken/webrevs/8232084.0_jdk11/

original  change :


https://hg.openjdk.java.net/jdk/jdk/rev/9f5b92d5a1b2

Thanks, Matthias