lldb-mi allocating memory inside of signal handlers

Hi all,

I noticed these thread sanitizer warnings while running lldb-mi tests on Linux.

WARNING: ThreadSanitizer: signal-unsafe call inside of a signal (pid=39721)

#0 operator new(unsigned long) :0 (lldb-mi-3.7.0+0x000000092b9d)

#1 std::string::_Rep::_S_create(unsigned long, unsigned long, std::allocator const&) :0 (libstdc++.so.6+0x0000000ba3b8)

#2 CMICmnResources::GetStringFromResource(unsigned int, CMIUtilString&) const /usr/local/google/home/vharron/ll/tot/llvm/tools/lldb/tools/lldb-mi/MICmnResources.cpp:434 (lldb-mi-3.7.0+0x00000014ddd8)

#3 CMICmnResources::GetString(unsigned int) const /usr/local/google/home/vharron/ll/tot/llvm/tools/lldb/tools/lldb-mi/MICmnResources.cpp:371 (lldb-mi-3.7.0+0x00000014db81)

#4 sigwinch_handler(int) /usr/local/google/home/vharron/ll/tot/llvm/tools/lldb/tools/lldb-mi/MIDriverMain.cpp:99 (lldb-mi-3.7.0+0x0000001589ff)

#5 __tsan::CallUserSignalHandler(__tsan::ThreadState*, bool, bool, int, my_siginfo_t*, void*) tsan_interceptors.o:0 (lldb-mi-3.7.0+0x00000009f25f)

#6 void std::this_thread::sleep_for<long, std::ratio<1l, 1000l> >(std::chrono::duration<long, std::ratio<1l, 1000l> > const&) /usr/bin/…/lib/gcc/x86_64-linux-gnu/4.8/…/…/…/…/include/c++/4.8/thread:279 (lldb-mi-3.7.0+0x00000013243e)

#7 CMIDriver::ReadStdinLineQueue() /usr/local/google/home/vharron/ll/tot/llvm/tools/lldb/tools/lldb-mi/MIDriver.cpp:710 (lldb-mi-3.7.0+0x000000155e62)

#8 CMIDriver::DoMainLoop() /usr/local/google/home/vharron/ll/tot/llvm/tools/lldb/tools/lldb-mi/MIDriver.cpp:631 (lldb-mi-3.7.0+0x000000155d37)

#9 non-virtual thunk to CMIDriver::DoMainLoop() /usr/local/google/home/vharron/ll/tot/llvm/tools/lldb/tools/lldb-mi/MIDriver.cpp:648 (lldb-mi-3.7.0+0x000000155fbd)

#10 CMIDriverMgr::DriverMainLoop() /usr/local/google/home/vharron/ll/tot/llvm/tools/lldb/tools/lldb-mi/MIDriverMgr.cpp:340 (lldb-mi-3.7.0+0x000000159ee6)

#11 main /usr/local/google/home/vharron/ll/tot/llvm/tools/lldb/tools/lldb-mi/MIDriverMain.cpp:364 (lldb-mi-3.7.0+0x000000158f60)