Hi,

Envoy (https://github.com/envoyproxy/envoy) depends on the RE2 library, and, like RE2, fuzzes components continuously using libfuzzer. Some fuzzers depend on the behavior of the RE2 library, and expect that the RE2 library is processing some regex.

The FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION is used in Envoy, but when fuzzers are compiled with this macro, we change the behavior of the RE2 library which uses this macro as well.

Is it possible to replace the macro in this library with a custom RE2_FUZZ macro that can be passed in as a flag in the oss-fuzz build? https://github.com/google/oss-fuzz/blob/master/projects/re2/build.sh. I don't see it used to build fuzzers in this repository, but maybe the macro should also be added when building the fuzzer in the makefile.

I would be willing to put out a fix PR for this here and in OSS-Fuzz.