Modify Makefile to override input variables CXXFLAGS and LDFLAGS
Update makefile to prevent wrong paths being put into .d files when LLVM_SRC or LLVM_BUILD is empty
Remove extra semi-colons from auto-generated code.
Regenerate auto-generated headers with new generate.pl script
Fix warnings in non-autogenerated files.

1. Remove unnecessary semi-colons.
2. Remove commas at the end of enumerator lists.
3. Use casts with the ternary operator to ensure both alternatives have the
   same type.
4. Remove asserts that unsigned values are greater than or equal to zero.
Update Makefile to place the generated .d files in build directories
Merge remote-tracking branch 'hsa/master'