This is an NFC commit to refactor the "load dependent files" parameter
from a boolean to an enum value. We want to be able to specify a
default, in which case we decide whether or not to load the dependent
files based on whether the target is an executable or not (i.e. a
dylib).
This is a dependency for D51934.
Differential revision: https://reviews.llvm.org/D51859
llvm-svn: 342633
f9a07e9f8d