[parse_tag] Accept non-ALNUM in tag name
diff --git a/src/hb-common.cc b/src/hb-common.cc
index 282a8e4..bd4cd88 100644
--- a/src/hb-common.cc
+++ b/src/hb-common.cc
@@ -815,7 +815,7 @@
   }
 
   const char *p = *pp;
-  while (*pp < end && (ISALNUM(**pp) || **pp == '_'))
+  while (*pp < end && (**pp != ' ' && **pp != '=' && **pp != '['))
     (*pp)++;
 
   if (p == *pp || *pp - p > 4)