From MacPython/openblas-libs#163:
cblas.h contains
typedef void (*scipy_openblas_dojob_callback)64_(int thread_num, void *jobdata, int dojob_data);
typedef void (*scipy_openblas_threads_callback)64_(int sync, ...
Note the stray 64_, which should be follow the callback and not the ). This build is defining these arguments to make:
SYMBOLSUFFIX=64_ LIBNAMESUFFIX=64_ SYMBOLPREFIX=scipy_ LIBNAMEPREFIX=scipy_ FIXED_LIBNAME=1
I am not sure how those headers are getting generated. cc @serge-sans-paille