Please forgive my poor understanding of C, but is it possible to add the missing features as extra options/files/headers so you can pick and choose which features you want to enable and/or include?
There already defines to include\exclude features: H264E_MAX_THREADS=n, H264E_SVC_API=1, MINIH264_ONLY_SIMD.
Complete documentation still in progress and subject to change. For now only comments in minih264e.h and minih264e_test.c can tell how to use it.