clang 3.7.0 memory sanitizer - uninitialized value

[mintyc]

using clang 3.7.0 with gcc 4.8.3's stdlibc++ on Centos 7 with 3.0.0-beta-1
export CXXFLAGS="-fsanitize=memory -fsanitize-memory-track-origins=2 -fno-omit-frame-pointer"
then build and run tests
Gives a traced Warning of use of uninitialized value...

StaticDescriptorInitializer_google_2fprotobuf_2fany_2eproto constructor()
calls AddDesc...
stack down to
SimpleDescriptorDatabase::DescriptorIndex<>AddFile() - this function has comments to read....
in descriptor_database.cc
// We must be careful here -- calling file.package() if file.has_package() is
// false could access an uninitialized static-storage variable if we are being
// run at startup time.

uininitialized value reported down through AddSymbol() to ValidateSymbolName()

Sanitizer stops at the first problem, so there may be others.

[haberman]

According to #1099 protobuf is msan-clean, and errors are likely due to a misbuilt/misconfigured libstdc++. I also just ran msan against our protobuf test suite internally and it was clean.