ifndef-define-typo

Tries to find cases where a #define following an #ifndef defines a different but similar name.

Example:

#ifndef GL_FRAMEBUFFER_SRG // Oops, typo.
# define GL_FRAMEBUFFER_SRGB 0x8DB9
#endif

This check uses a Levenshtein Distance algorithm so it will only warn if the names are similar. This check is disabled by default as it will report many false-positives.