Fix more LLVM 3.4 debug info problems.

The expression llvm::DIType(NULL) is not accepted by LLVM.
This commit replaces this with an unspecified type (which is
new in LLVM 3.4).
Add eh_collision stub for Win64
Fix for issue #461
Add test case for issue #461
Possible fix to issue #451
Fix for issue #467
Reverting last commit as it breaks a test
Fix for issue #467 and partial fir for issue #455
Add version identifier for AArch64
Remove leftover D1-only comment.
Add types for Linux/AArch64.
Fix broken merge
Changed mangling for naked assembler on Win32.

Reported by Temtaime on the newsgroup!
Enabling multi-lib build for LLVM 3.3.

The required libs are only installed if OPTS contains the string "MULTILIB=ON".
In order to get the curl tests working with the dynamic lib an additional ln
is necessary.
Add missing types for Linux/ARM
Fix annoying clang warning about missing newline
Nested context creation code beautification.
Fix broken indentation in debug log output.
Added newline at end of file.
FuncDeclaration::nestedVars should only be filled in DtoCreateNestedContextType.