Introduces support for '.refsym' assembler directive.
From GCC docs (for MSP430):
'.refsym' - This directive instructs assembler to add an undefined reference
to the symbol following the directive. No relocation is created for this symbol;
it will exist purely for pulling in object files from archives.
Patch by Kristina Bessonova!
Differential Revision: https://reviews.llvm.org/D54618
llvm-svn: 347041
411773d227