* src/scan-skel.l: Output the base name parts of the parser and

header file names.
* tests/output.at (AT_CHECK_OUTPUT): Support subdirectorioes, and
additional checks.
Use this to exercise C++ outputs in subdirs.
Reported by Oleg Smolsky.

src/system.h

@@ -62,6 +62,9 @@ typedef size_t uintptr_t;
 
 #include <stpcpy.h>
 
+/* From lib/basename.c. */
+char *base_name (char const *name);
+
 
 /*-----------------.
 | GCC extensions.  |