fix and add test for Proc#source_location
error.h: add extern "C" for C++
visualcpp toolchain: change compiler/linker flags

with these flags visualcpp should behave more like the gcc toolchain

c:
- produce debug information
- optimize for speed instead of disabling optimization
- use non-debug version of Microsoft's C library
- remove unused and unnecessary macro definitions
cxx:
- separate C and C++ (#1594)
- specify kind of exception handling (see warning C4530)
linker:
- produce debug information
- disable incremental linking and re-enable optimizations
Merge pull request #1816 from cremno/error.h-add-extern_c

error.h: add extern "C" for C++
Merge pull request #1817 from cremno/visualcpp-toolchain-change-cflags

visualcpp toolchain: change compiler/linker flags
Merge pull request #1815 from take-cheeze/source_location

Fix and add test for Proc#source_location.