On aarch64, char is unsigned by default, so *buf < 0x20 never held for
bytes >= 0x80, causing strDfa.scan to be skipped for multi-byte UTF-8
sequences in batch mode. Cast to int8_t to get the same signed comparison
used by the SIMD path.
Also add aarch64-symbol-imports.txt with the GLIBC 2.17 versioned symbols
imported by the library on that platform.