On Linux/x86-64, Internal assembly functions are exported:
$ nm -D lib/libzstd.so.1| grep usingDTable_internal_bmi2_asm_loop
00000000000c23c0 T _HUF_decompress4X1_usingDTable_internal_bmi2_asm_loop
00000000000c23c0 T HUF_decompress4X1_usingDTable_internal_bmi2_asm_loop
00000000000c283d T _HUF_decompress4X2_usingDTable_internal_bmi2_asm_loop
00000000000c283d T HUF_decompress4X2_usingDTable_internal_bmi2_asm_loop
These are internal functions and shouldn't be exported.