Fix compiler warnings
Some unused variables, avoid clobbering variables when longjmp/setjmp in image-loader, using format specifier for printing 64-bit variables for both 32 and 64-bit architectures.
Tested with some older versions of gcc: 4.4, 4.6, 4.9 (debian snapshots for armel) and gcc-7.3 armv7 from yocto.
Signed-off-by: Marius Vlad marius.vlad0@gmail.com