Fix GCC -Wconversion warning in C utility code (GH-4854)
Fix GCC -Wconversion warning in C utility code (GH-4854)

scoder/cython,da-woods/cython,scoder/cython,cython/cython,cython/cython,da-woods/cython,da-woods/cython,cython/cython,cython/cython,scoder/cython,scoder/cython,da-woods/cython