Move use of __warnattr to __deprecated.

clang don't support warning attribute. Replacing warning attriubte with
deprecated attribute can achieve the same behavior whether compiled by
gcc or clang.

Bug: 19340053
Change-Id: I064432b81cf55212458edbc749eb72dc15a810fb
diff --git a/libc/include/stdio.h b/libc/include/stdio.h
index b04aa24..f3bfae0 100644
--- a/libc/include/stdio.h
+++ b/libc/include/stdio.h
@@ -266,16 +266,16 @@
 
 #ifndef __AUDIT__
 #if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 201112L
-char* gets(char*) __warnattr("gets is very unsafe; consider using fgets");
+char* gets(char*) __deprecated("gets is very unsafe; consider using fgets");
 #endif
 int sprintf(char* __restrict, const char* __restrict, ...)
-    __printflike(2, 3) __warnattr("sprintf is often misused; please use snprintf");
-char* tmpnam(char*) __warnattr("tmpnam possibly used unsafely; consider using mkstemp");
+    __printflike(2, 3) __deprecated("sprintf is often misused; please use snprintf");
+char* tmpnam(char*) __deprecated("tmpnam possibly used unsafely; consider using mkstemp");
 int vsprintf(char* __restrict, const char* __restrict, __va_list)
-    __printflike(2, 0) __warnattr("vsprintf is often misused; please use vsnprintf");
+    __printflike(2, 0) __deprecated("vsprintf is often misused; please use vsnprintf");
 #if __XPG_VISIBLE
 char* tempnam(const char*, const char*)
-    __warnattr("tempnam possibly used unsafely; consider using mkstemp");
+    __deprecated("tempnam possibly used unsafely; consider using mkstemp");
 #endif
 #endif