handle malloc(0) and free(0) in corruption checker
simplify corruption canary
support realloc in corruption checker
allow changing frequency of corruption checks, and forcing a check irregardless of frequency
Provide error message on invalid command to emmake.

Previously, this would just throw an exception, now it provides
a reasonable error message.
Statically allocate the strtok state block so it doesn't trip up our leak detection.
Mix_Init
Improvement of the Fullscreen patch:
- SDL_WM_ToggleFullScreen now delivers the proper return value,
  especially when failing to initiate full screen mode

Signed-off-by: Michael Riss <Michael.Riss@gmx.de>
Further improvement of the full screen support:
- SDL_WM_ToggleFullScreen now delivers correct return values,
  reflecting that for a SDL program it's impossible
  to switch to full screen mode in the browser environment

Signed-off-by: Michael Riss <Michael.Riss@gmx.de>
vertex array object support in gl emulation
glGetPointerv
TODO: multiple array buffers in vao (for each vertex attrib pointer separately)
In allocate() only query native type size when needed
add more glGetIntegerv constants
build base type_info class with libcxxabi, fixes #862
remove bad_cast/typeinfo.cpp from libcxx, no longer needed since it is in libcxxabi
do not wipe out llvm debug info if linespecific corrections are done
do not forward enable/disable of GL_TEXTURE_2D to WebGL enable/disable, it is not needed and just warns
Added some comments
emcc: Improve handling of -O flag.

Previously, while gcc supports -O, emcc would fail. It now interprets
-O as -O2, just as gcc does.

Additionally, it was only looking at the first character after -O, so
nonsense like -O34 would be accepted (and treated as -O3).