gen_tray SDK defects

[TomyLobo]

the gen_tray source code provided with the winamp SDK 5.02, as available from NSDN, has a number of defects:

1.
winamp's main window is sub-classed but never un-subclassed
since winamp possibly calls FreeLibrary on gen_tray.dll before destroying its main window, this might cause windows to call a window procedure in an invalid piece of memory.
(the fix is present in the Winamp 5.34 (BETA) SDK, but for some reason it's commented.)

2.
by default, the code does not work when compiled as C++
being the only gen plugin example provided with the SDK, it should at least do that. the required changes are minimal.
(still present in Winamp 5.34 (BETA) SDK)

3.
there is a file called "systray.c" that is not used in the project file
(fixed in Winamp 5.34 (BETA) SDK)

4.
the headers lack header guards
(fixed in Winamp 5.34 (BETA) SDK)


in the Winamp 5.34 (BETA) SDK, 1. and 2. remain.
i consider 1. to be a bug that should be fixed, even more so if it is present in the version of gen_tray that is distributed with winamp.

2. is an SDK defect, that can cause confusion with people oblivious of the differences between C and C++