RFR: JDK-8251533 MacOS build of libjimage explicitly adds C++ standard library

Thu Aug 13 12:00:52 UTC 2020

 From the bug report:

In CoreLibraries.gmk we have

$(eval $(call SetupJdkLibrary, BUILD_LIBJIMAGE, \
...
???LIBS_unix := -ljvm -ldl $(LIBCXX), \
???LIBS_macosx := -lc++, \

I think the LIBS_macosx line should not be needed. Other similar places 
don't seem to do that. If it were necessary to explicitly add the C++ 
standard library to the link command, that would be better done by 
setting up LIBCXX.

Bug: https://bugs.openjdk.java.net/browse/JDK-8251533
WebRev: 
http://cr.openjdk.java.net/~ihse/JDK-8251533-libjimage-links-with-lc++/webrev.01

/Magnus