Fix for problem with undeclared intptr_t type
When building gnu-efi with old compilers with pre C90 compilers:
In file included from gnu-efi-3.0.9/lib/../inc/efilib.h:25:0,
from gnu-efi-3.0.9/lib/lib.h:24,
from gnu-efi-3.0.9/lib/dpath.c:25:
gnu-efi-3.0.9/lib/dpath.c: In function 'FileDevicePath':
gnu-efi-3.0.9/lib/../inc/efilink.h:145:47: error: 'intptr_t' undeclared (first use in this function)
#define EFI_FIELD_OFFSET(TYPE,Field) ((UINTN)(intptr_t)(&(((TYPE *) 0)->Field)))
Problem introduced with commit
a46a62b12b58139c31d4288384808365c4053bf2
(Fix some types gcc doesn't like).
Avoid this by adding intptr_t (and uintptr_t) typedefs for builds that does
not include stdint.h.
Signed-off-by: Esben Haabendal <esben@esben1.localdomain>