Major code cleanup.

- Make all internal functions "static".
- Make sure each module's header and implementation file match.
- Remove all library-like functionality from main.c, so only
  the actual frontend remains in main.c.
- Add C++ brackets to all header files.

That effectively leaves the various module C files as something like
an "avrdude library", with main.c being the currently only frontend
program for that library.  In theory, it should be possible to write
different frontends using the same library backend functions though.


git-svn-id: svn://svn.savannah.nongnu.org/avrdude/trunk/avrdude@722 81a1dc3b-b13d-400b-aceb-764788c761c2

usbasp.h

@@ -50,6 +50,14 @@
 #define USB_ERROR_ACCESS    2
 #define USB_ERROR_IO        3
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 void usbasp_initpgm (PROGRAMMER * pgm);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* usbasp_h */