Compiling using CLANG gives the following errors:
Undefined symbols for architecture x86_64:
"_bwt_occ", referenced from:
_bwt_cal_sa in bwt.o
_bwt_sa in bwt.o
"_bwt_2occ", referenced from:
_bwt_match_exact in bwt.o
_bwt_match_exact_alt in bwt.o
_bwt_cal_width in bwtaln.o
"_bwt_2occ4", referenced from:
_bwt_match_gap in bwtgap.o
_bsw2_core in bwtsw2_core.o
"_bwtl_2occ4", referenced from:
_bsw2_core in bwtsw2_core.o