Remove gcc-4.8 patches from master
Update gcc-4.9 patches
Fix memory bug in large compilations
Bug 118 - ICE in gimplifying TRY_CATCH_EXPR
Provide access to target attributes via gcc.attribute
Handle noclone attribute
Convert symbols to expression type, fixes #115
Default deprecation warnings to 'off'.

This is purely for compatibility with build systems, and given GDC's
-Werror controls both compiler warnings and deprecations, as opposed to
a separate error switch.
Refacter target-ver-syms.sh - have no further need for d_unix or d_versym_os.
Propogate NRVO functions to delegates.
Branch gdc-4.9
Switch master patches over to GCC's next development cycle.
Update target-ver-syms for MinGW

We do not have/need libm on MiGW
Trivial build fixes for MinGW/druntime
Implement GDC-vararg handling in std.format for MinGW
GDC inline ASM fixes for MinGW
Extern variable _CRT_MT is __gshared
MinGW64 does not provide __imp symbols for InterlockedExchange
Thread, Fiber & GC support for MinGW
Fix main function for MinGW