Index: heromesh.h
==================================================================
--- heromesh.h
+++ heromesh.h
@@ -2,11 +2,11 @@
   This file is part of Free Hero Mesh and is public domain.
 */
 
 // == main ==
 
-#define fatal(...) do{ fprintf(stderr,__VA_ARGS__); exit(1); }while(0)
+#define fatal(...) do{ fprintf(stderr,"FATAL: " __VA_ARGS__); exit(1); }while(0)
 #define boolxrm(a,b) (*a=='1'||*a=='y'||*a=='t'||*a=='Y'||*a=='T'?1:*a=='0'||*a=='n'||*a=='f'||*a=='N'||*a=='F'?0:b)
 
 #define TY_NUMBER 0
 #define TY_CLASS 1
 #define TY_MESSAGE 2