Fix issue #40. Properly flush stdio's streams at exit.

src/libc/stdio/Makefile

@@ -13,7 +13,7 @@ SRCS		= ${STDSRC} fgetc.c fgets.c fputc.c fputs.c gets.c puts.c \
 OBJS		= ${STDOBJ} fgetc.o fgets.o fputc.o fputs.o gets.o puts.o \
                   feof.o ferror.o fileno.o
 
-STDSRC		= clrerr.c doscan.c exit.c fdopen.c filbuf.c findiop.c \
+STDSRC		= clrerr.c doscan.c exit.c clnup.c fdopen.c filbuf.c findiop.c \
 		  flsbuf.c fopen.c fprintf.c fread.c freopen.c fseek.c \
 		  ftell.c fwrite.c getchar.c getw.c printf.c putchar.c putw.c \
 		  rew.c scanf.c setbuf.c setbuffer.c setvbuf.c snprintf.c sprintf.c \

src/libc/stdio/clnup.c

@@ -0,0 +1,8 @@
+/*
+ * This stub is linked in, when application uses no stdio calls.
+ */
+__attribute__((weak))
+void _cleanup()
+{
+        /* Nothing to do. */
+}

src/libc/stdio/exit.c

@@ -3,14 +3,7 @@
 
 int errno;
 
-/*
- * This stub is linked in, when application uses no stdio calls.
- */
-__attribute__((weak))
-void _cleanup()
-{
-        /* Nothing to do. */
-}
+extern void _cleanup();
 
 void
 exit (code)