building on macosx 10.14.4 using Xcode 10.2.1 fails:

/Users/johan/openjdk/jdk/test/hotspot/gtest/classfile/test_symbolTable.cpp:62:6: error: explicitly assigning value of variable of type 'TempNewSymbol' to itself [-Werror,-Wself-assign-overloaded]
  s1 = s1; // self assignment
  ~~ ^ ~~
1 error generated.

The following patch fixes this:

diff -r 0907dce4b90e make/hotspot/lib/CompileGtest.gmk
--- a/make/hotspot/lib/CompileGtest.gmk Thu May 02 22:52:51 2019 +0100
+++ b/make/hotspot/lib/CompileGtest.gmk Fri May 03 14:39:01 2019 +0200
@@ -76,7 +76,7 @@
     DISABLED_WARNINGS_gcc := $(DISABLED_WARNINGS_gcc) \
         undef, \
     DISABLED_WARNINGS_clang := $(DISABLED_WARNINGS_clang) \
- undef switch format-nonliteral tautological-undefined-compare, \
+ undef switch format-nonliteral tautological-undefined-compare self-assign-overloaded, \
     DISABLED_WARNINGS_solstudio := $(DISABLED_WARNINGS_solstudio) \
         identexpected, \
     DISABLED_WARNINGS_microsoft := $(DISABLED_WARNINGS_microsoft) \