Added test programs for the exec() function.

testcode/lib/exec-test1.c

@@ -0,0 +1,24 @@
+/*
+** These programs test CC65's exec() program-chaining function.
+** exec-test1 runs exec-test2 -- that tests the loading and starting of another
+** program.  Then, exec-test2 runs arg-test -- that tests command-line argument
+** passing.
+**
+** 2013-08-24, Greg King
+*/
+
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <conio.h>
+
+int main (void) {
+    clrscr ();
+    cprintf ("\nExec-test #1 -- launching #2...\r\n");
+
+    exec ("exec-test2", "");
+
+    cprintf ("\nFailed to find #2:\r\n %s.\r\n", _stroserror (_oserror));
+    cgetc ();
+    return _oserror;
+}