* libc/include/ctype.h: __CYGWIN32__ -> __CYGWIN__

* libc/include/ctype.h: __CYGWIN32__ -> __CYGWIN__
* libc/include/malloc.h: Ditto.
* libc/include/process.h: Ditto.
* libc/include/stdio.h: Ditto.
* libc/include/stdlib.h: Ditto.
* libc/include/time.h: Ditto.
* libc/include/machine/setjmp.h: Ditto.
* libc/include/sys/errno.h: Ditto.
* libc/include/sys/signal.h: Ditto.
* libc/include/sys/stat.h: Ditto.
* libc/include/sys/time.h: Ditto.
* libc/include/sys/unistd.h: Ditto.
* libc/include/string.h: Ditto.  strsignal should return a const char *.