fuzz: compile xdiff.cc with -std=c++17
Otherwise the build would fail as follows:
In file included from xdiff.cc:13:
./fuzzutil.h:23:10: fatal error: 'third_party/absl/types/optional.h' file not
found
#include "third_party/absl/types/optional.h"
--- a/contrib/fuzz/Makefile Sun Jun 03 13:12:32 2018 +0900
+++ b/contrib/fuzz/Makefile Sun Jun 03 13:18:13 2018 +0900
@@ -34,6 +34,7 @@
-o $@ \
$<
+xdiff: CXXFLAGS += -std=c++17
xdiff: xdiff.cc xdiffi.o xprepare.o xutils.o fuzzutil.o
$(CXX) $(CXXFLAGS) -DHG_FUZZER_INCLUDE_MAIN=1 -g -O1 -fsanitize=fuzzer-no-link,address \
-I../../mercurial xdiff.cc \