This patchs fixes warnings generated by older toolchains:
shared/image-loader.c: In function 'load_png':
shared/image-loader.c:211:12: warning: variable 'data' might be clobbered by 'longjmp' or 'vfork' [-Wclobbered]
png_byte *data = NULL;
See https://linux.die.net/man/3/longjmp why is this needed.
Signed-off-by: Marius Vlad <marius.vlad0@gmail.com>