Initial checkin of a portable framework for writing small GUI puzzle

games.

[originally from svn r4138]

gtk.c

@@ -0,0 +1,23 @@
+/*
+ * gtk.c: GTK front end for my puzzle collection.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+
+#include "puzzles.h"
+
+void fatal(char *fmt, ...)
+{
+    va_list ap;
+
+    fprintf(stderr, "fatal error: ");
+
+    va_start(ap, fmt);
+    vfprintf(stderr, fmt, ap);
+    va_end(ap);
+
+    fprintf(stderr, "\n");
+    exit(1);
+}