[libFuzzer] Add a missing include_directories.

[dokyungs]

Summary

FuzzerInterceptors.cpp includes <sanitizer/common_interface_defs.h>, and this patch adds a missing include_directories to make sure the included file is found.

[morehouse]

We should avoid linking with sanitizer_common, but as long as its only includes I think we're fine.

[dmajor]

I've confirmed that this fixes our builds, thank you.

compiler-rt/lib/fuzzer/CMakeLists.txt

set(LIBFUZZER_HEADERS
   FuzzerMutate.h
   FuzzerOptions.h
   FuzzerRandom.h
   FuzzerSHA1.h
   FuzzerTracePC.h
   FuzzerUtil.h
   FuzzerValueBitMap.h)
 
+include_directories(../../include)
+
 CHECK_CXX_SOURCE_COMPILES("
   static thread_local int blah;
   int main() {
   return 0;
   }
   " HAS_THREAD_LOCAL)
 
 set(LIBFUZZER_CFLAGS ${SANITIZER_COMMON_CFLAGS})