[PECOFF] Use replace_extension() instead of doing it myself.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@186612 91177308-0d34-0410-b5e6-96231b3b80d8
Add support for -all_load. Enhance DarwinLdDriverTest unit test test cases to test all options parsed so far

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@186626 91177308-0d34-0410-b5e6-96231b3b80d8
Check the return value from parse()

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@186630 91177308-0d34-0410-b5e6-96231b3b80d8
Add -help option to Darwin Driver.  Use grouping in Options table to better format help output

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@186640 91177308-0d34-0410-b5e6-96231b3b80d8
[PECOFF][Driver] Add -libpath command line option.

The logic to search a library from the library paths will be implemented
in a different patch.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@186644 91177308-0d34-0410-b5e6-96231b3b80d8
[PECOFF] Use library search path when looking for a .lib file.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@186645 91177308-0d34-0410-b5e6-96231b3b80d8