clock_t is defined in <time.h>, but not <sys/time.h> in newlib 4.1.0.
this fixes a compile error in files including this header:
In file included from psp-elf/bin/../psp/sdk/include/pspuser.h:25:0,
from psp-elf/bin/../psp/sdk/include/pspkernel.h:17,
from ./include/driver/me.h:5,
from src/me.c:1:
psp-elf/bin/../psp/sdk/include/psputils.h:51:1: error: unknown type name 'clock_t'
make[1]: *** [src/me.o] Error 1
encountered while trying to compile MElib.
