Fixes compilation/run error with BUILD_SHARED_LIBS=TRUE

BUILD_SHARED_LIBS=TRUE currently isn't working for Linux x86_64
This patch fixes the link errors and also some runtime errors

Test Plan:
CC=clang CXX=clang++ cmake -GNinja -DBUILD_SHARED_LIBS=TRUE -DCMAKE_LINKER=ld.gold -DCMAKE_BUILD_TYPE=Debug ../../llvm
ninja
ninja check-lldb

llvm-svn: 226039