Don't discard definitions of common symbols. Not sure if this is the right fix.

Before this change, the program:
  int var;
  int main(void) { return 0; }
when run under 'nm -g' would show 'U var' with the gold plugin and
'B var' with gcc.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64616 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed