Merge /u/gmbr3/gnu-efi/ branch unsigned-char into master

https://sourceforge.net/p/gnu-efi/code/merge-requests/47/

Make.defaults

@@ -184,11 +184,11 @@ endif
 
 ifeq (FreeBSD, $(findstring FreeBSD, $(OS)))
 CFLAGS  += $(ARCH3264) -g -O2 -Wall -Wextra -Werror \
-           -fshort-wchar -fno-strict-aliasing \
+           -funsigned-char -fshort-wchar -fno-strict-aliasing \
            -ffreestanding -fno-stack-protector
 else
 CFLAGS  += $(ARCH3264) -g -O2 -Wall -Wextra -Wno-pointer-sign -Werror \
-           -fshort-wchar -fno-strict-aliasing \
+           -funsigned-char -fshort-wchar -fno-strict-aliasing \
 	   -ffreestanding -fno-stack-protector -fno-stack-check \
            -fno-stack-check \
            $(if $(findstring gcc,$(CC)),-fno-merge-all-constants,)