jehanne: fix usleep

newlib/libc/sys/jehanne/syscalls.c

@@ -21,6 +21,7 @@
 #include <reent.h>
 
 typedef unsigned long clock_t;
+typedef unsigned long useconds_t;
 
 extern void initialize_newlib(void);
 static void newlib(int argc, char *argv[]) __attribute__((noreturn));
@@ -200,6 +201,13 @@ sleep(unsigned int seconds)
 	return POSIX_sleep(seconds);
 }
 
+int
+usleep(useconds_t usec)
+{
+	int *errnop = &_REENT->_errno;
+	return POSIX_usleep(errnop, usec);
+}
+
 int
 pipe(int fildes[2])
 {