When testing with newer compilers and newlib, a mismatch surfaced in
the definition of intptr_t, int32_t, uint32_t.  I don't know why the
library header gets picked up.

This patch, though ugly, fixes the problem by using the "ifdef" names
found in lm32-elf/include/sys/_stdint.h (the offending file).
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>