Revert "Remove __sinit and __sdidinit."

This reverts commit 4371961e00ad83fca033992c8a19c7d262fe6f84.

This broke booting; ueventd crashes with a null pointer dereference
somewhere in __sfp (but the kernel doesn't unwind, so I don't know
what was calling __sfp).

Change-Id: I65375fdfdf1d339a06558b4057b580cacd6324e2
diff --git a/libc/stdio/refill.c b/libc/stdio/refill.c
index 5b0811f..e87c7b9 100644
--- a/libc/stdio/refill.c
+++ b/libc/stdio/refill.c
@@ -51,6 +51,11 @@
 int
 __srefill(FILE *fp)
 {
+
+	/* make sure stdio is set up */
+	if (!__sdidinit)
+		__sinit();
+
 	fp->_r = 0;		/* largely a convenience for callers */
 
 #if !defined(__ANDROID__)