Notes:Software fallback warnings

Enable software fallback warnings
The run-time option "software-warn" makes DirectFB show warnings whenever a software fallback method is used.

root@embedded:~> DFBARGS=software-warn gtk-demo [...] (!!!) *** WARNING [Blit          (  23, 270-   1x   8) ARGB, flags 0x00000005, color 0xff000000, source ( 123,   0) ARGB] *** [generic.c:7945 in gBlit]

Use the mechanism to see all rendering operations
Adding "no-hardware" will cause software fallbacks all the time, hence showing every rendering operation made.

root@embedded:~> DFBARGS=software-warn,no-hardware gtk-demo [...] (!!!) *** WARNING [FillRectangle (   2, 264- 200x  20) ARGB, flags 0x00000000, color 0xffffffff] *** [generic.c:7823 in gFillRectangle] (!!!) *** WARNING [Blit          (   0,   0- 123x   9) ARGB, flags 0x00000000, color 0x00000000, source (   0,   0) ARGB] *** [generic.c:7945 in gBlit] (!!!) *** WARNING [Blit          (  23, 270-   1x   8) ARGB, flags 0x00000005, color 0xff000000, source ( 123,   0) ARGB] *** [generic.c:7945 in gBlit]