Re: [PATCH] Fix compilation erorr when --enable-gcc-warnings passed

[Paul Eggert]

Alexander Kuleshov wrote:
> And seems that this version of the lookup_rgb_color() is only for these 
> platforms, because I see that the src/image.c contains yet another 
> implementation of the lookup_rgb_color() for platforms where 
> COLOR_TABLE_SUPPORT is enabled.

Although there are two lookup_rgb_color implementations, the buggy one is 
invoked if USE_CAIRO, and this generates garbage on the screen. I have filed a 
bug report; see:

http://bugs.gnu.org/22442

I installed a patch into emacs-25 to replace the compile-time warning with a 
run-time crash, if you configure --with-cairo --enable-checking and visit a .png 
file. This patch should also fix the other warnings you noticed, albeit in 
different ways sometimes.

Thanks for doing this checking! It found a real bug.