Fixed initialization of __Pyx_CachedCFunction in the LIMITED_API (GH-3379)
Fixed initialization of __Pyx_CachedCFunction in the LIMITED_API (GH-3379)

Strings werren't static for the limited API so had to be set at module init rather than compile time.
da-woods/cython,cython/cython,scoder/cython,cython/cython,cython/cython,da-woods/cython,scoder/cython,scoder/cython,da-woods/cython,da-woods/cython,cython/cython,scoder/cython