fix compiling on Mac with non-GZIP kernel compressions

  * Non-GZIP compressions do not include the size in the file. Makefile.lib
    uses the stat command to determine the size of the file and then append
    the file size to the end of the image.
  * On BSD systems like Mac, stat does not recognize -c "%s" instead it
    needs -f "%z". This resulted in a non-booting kernel since the appended
    file size was either corrupt or 0.
  * Run both forms of stat, using whichever does not error out.

Change-Id: I95fd913074db90bb2b4afd8a2667246bea4a62e3

scripts/Makefile.lib

@@ -229,10 +229,11 @@ cmd_dtc = $(objtree)/scripts/dtc/dtc -O dtb -o $@ -b 0 $(DTC_FLAGS) $<
 
 # Bzip2 and LZMA do not include size in file... so we have to fake that;
 # append the size as a 32-bit littleendian number as gzip does.
+# -- the first stat call is for GNU stat, the second for BSD stat
 size_append = printf $(shell						\
 dec_size=0;								\
 for F in $1; do								\
-	fsize=$$(stat -c "%s" $$F);					\
+	fsize=$$(stat -c "%s" $$F 2>/dev/null || stat -f "%z" $$F); \
 	dec_size=$$(expr $$dec_size + $$fsize);				\
 done;									\
 printf "%08x\n" $$dec_size |						\