The code uses some constructs that cause compilers to spit out warnings. As
they do no harm, one should be able to turn off such warnings and enable others
if needed.
Some functions that ought to return a value call return without any value. This
commit adds a dummy value to each of those returns so that clang stops
complaining.
The source code for handling images has a double free problem. Recent versions
of the GNU libc have a mechanism to automagically abort the program in such a
case. This causes Mosaic to crash if images are displayed.
I work around this issue by turning of automatical program abortion with a call
to mallopt().
