gcc 4 cleanups (mostly unsigned char* vs char*)

stralloc/stralloc_copyb.c

@@ -4,7 +4,7 @@
 /* stralloc_copyb copies the string buf[0], buf[1], ..., buf[len-1] into
  * sa, allocating space if necessary, and returns 1. If it runs out of
  * memory, stralloc_copyb leaves sa alone and returns 0. */
-int stralloc_copyb(stralloc *sa,const unsigned char *buf,unsigned long int len) {
+int stralloc_copyb(stralloc *sa,const char *buf,unsigned long int len) {
   if (stralloc_ready(sa,len)) {
     sa->len=len;
     byte_copy(sa->s,len,buf);