cmake: Add additional libraries to fix the darwin shared library build

darwin requires the additional linkages of...

LLVMBitReader
LLVMMCParser
LLVMObject
LLVMProfileData
LLVMTarget
LLVMVectorize

as the darwin requires all of the weak undefined symbols in a library to be
resolved when linking it against an executable (unless
-Wl,-undefined,dynamic_lookup is used to override the default behavior of
-Wl,-undefined,error).

Contributed-by: Jack Howarth
llvm-svn: 259332