archivers/c-blosc2: fix build on powerpc64le

In file included from /wrkdirs/usr/ports/archivers/c-blosc2/work/c-blosc2-2.0.4/plugins/codecs/ndlz/xxhash.h:2937:
/usr/lib/clang/11.0.1/include/altivec.h:55:19: error: unknown type name 'vector'
static inline vector bool char __ATTRS_o_ai