Building on linux/armv8

[clort81]

Building on aarch64, Makefile thinks I want PANDORA. So i changed the CFLAGS after else. I don't know wy $(LINUX) didn't = 1 (arm devuan)

else
 CFLAGS = -mcpu=native -Ofast -g `sdl-config --cflags` -I/usr/X11R6/include
 #CFLAGS = -DPANDORA -mcpu=cortex-a8 -mfpu=neon -mfloat-abi=softfp -ftree-vectorize -fsingle-precision-constant -g -Ofast `sdl-config --cflags` -I/usr/X11R6/include

After this build fails with:

src/auxiliar.cpp: In function ‘SDL_Surface* load_maskedimage(char*, char*, char*)’:
src/auxiliar.cpp:87:19: error: cannot convert ‘bool’ to ‘SDL_Surface*’ in return
   mask==0) return false;

changing 'false' to 'res' compiles, but it's probably not desireable. what would be a sensible return value if loading resources fails?

[ptitSeb]

It should be return NULL;, or return nullptr;. I'll fix that, and try to make some arragments in the makefile to not force Pandora.