Make examples' shebang use target tcc bindir path

Use @BINDIR@ in shebang of examples to put the right path on the target
system. That is, use #!/usr/local/bin/tcc if tcc is installed in /usr/local/bin
and #!/usr/bin/tcc if tcc is installed in /usr/bin/tcc.

examples/ex1.c

@@ -1,8 +0,0 @@
-#! /usr/local/bin/tcc -run
-#include <tcclib.h>
-
-int main()
-{
-    printf("Hello World\n");
-    return 0;
-}