get rid of gcc compiler warning

scan/scan_utf8_sem.c

@@ -1,14 +1,13 @@
 #include "scan.h"
 
 size_t scan_utf8_sem(const char* in,size_t len,uint32_t* num) {
-  size_t r=scan_utf8(in,len,num);
+  uint32_t tmp=0;
+  size_t r=scan_utf8(in,len,&tmp);
   if (r>0) {
-    // gcc -fanalyze warns here that we are reading undefined values
-    // from *num which is declared as write only. That is a false
-    // positive because we just called scan_utf8 which writes there.
-    if (*num>=0xd800 && *num<=0xdfff) return 0;
-    if ((*num&0xfffe)==0xfffe) return 0;
-    if (*num>=0xfdd0 && *num<=0xfdef) return 0;
+    if (tmp>=0xd800 && tmp<=0xdfff) return 0;
+    if ((tmp&0xfffe)==0xfffe) return 0;
+    if (tmp>=0xfdd0 && tmp<=0xfdef) return 0;
+    *num=tmp;
   }
   return r;
 }