Autotools: Sync quotes in PHP_INSTALL_HEADERS

Follow-up of GH-13213

[skip ci]

Author: petk

ext/hash/config.m4

@@ -45,4 +45,4 @@ EXT_HASH_HEADERS="php_hash.h php_hash_md.h php_hash_sha.h php_hash_ripemd.h \
   php_hash_xxhash.h xxhash/xxhash.h"
 
 PHP_NEW_EXTENSION(hash, $EXT_HASH_SOURCES, 0,,$PHP_HASH_CFLAGS)
-PHP_INSTALL_HEADERS(ext/hash, $EXT_HASH_HEADERS)
+PHP_INSTALL_HEADERS([ext/hash], [$EXT_HASH_HEADERS])