allow trim() public function

lib11sht.h

@@ -50,4 +50,10 @@ int sequal_full(char *a, char *b, float shold, float *ratio,
  */
 int fequal(float a, float b, float delta);
 
+/* String trim: removes leading + trailing whitespace (including UTF-8
+ * NBSP bytes 0xC2 / 0xA0) AND collapses internal runs of whitespace
+ * to a single space. Modifies s in place. Caller's buffer must already
+ * be NUL-terminated. */
+void trim(char *s);
+
 #endif /* LIB11SHT_H */