Build and include LLVM sanitizer libraries built by vcpkg

[ekilmer]

If we want to use the clang compiler built with vcpkg as a self-contained toolchain, we should also have the option to build the target project with the equivalent sanitizer support.

I think this might be enabled by building the compiler-rt project https://compiler-rt.llvm.org/

Initially, this should be limited to the Address and Undefined sanitizers at first, both to reduce release artifact blowup and because other sanitizers like Memory sanitizer require instrumented standard c++ library.

The following command should work in order to close this issue:

CXXFLAGS="-fsanitize=address -fno-omit-frame-pointer -fno-optimize-sibling-calls -ffunction-sections -fdata-sections -Wl,-undefined,dynamic_lookup" \
CFLAGS="-fsanitize=address -fno-omit-frame-pointer -fno-optimize-sibling-calls -ffunction-sections -fdata-sections -Wl,-undefined,dynamic_lookup" \
LDFLAGS="-fsanitize=address -Wl,-undefined,dynamic_lookup" \
cmake -G Ninja -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ \
  -DCMAKE_INSTALL_PREFIX=$(pwd)/install -DVCPKG_ROOT="/Users/ekilmer/src/cxx-common/vcpkg" ..

Currently, it errors with something like:

/usr/bin/ld: cannot find .... 
<vcpkg_root>/installed/x64-linux-rel/lib/clang/11.0.0/lib/linux/libclang_rt.asan-x86_64.a: No such file or directory