core.demangle.mangleFunc for different linkage types

- error out for extern(C++)
- preserve plain names for extern(C), extern(Pascal) and extern(Windows)
add static to kill pointless allocation
Merge pull request #624 from dawgfoto/mangleFunc

core.demangle.mangleFunc for different linkage types
Merge pull request #625 from adamdruppe/bug_10323

add static to kill pointless allocation
[Refactoring] Refactor `core.stdc.stdint`.
[Workaround] Add Issue 11173 workaround.

Issue URL: http://d.puremagic.com/issues/show_bug.cgi?id=11173
Merge pull request #516 from denis-sh/make-`core.stdc.stdint.typify`-public

Make `core.stdc.stdint.typify` public