These functions were the only inline C API functions. This makes it impossible to bind these useful functions from non-C languages via FFI as they rely on symbols for these functions existing.
With this PR a new libLLVMAllTargets.a static library is built which contains the non-inline implementations for the functions. I manually confirmed that the bin directory does not increase much in size and that libLLVM-4.0svn.so contains the newly added symbols.
Resubmission of https://reviews.llvm.org/D22734.