Fix fread returning bad data.

Bug: 19172514
Change-Id: I05016577858a02aca7d14e75e6ec28abc925037c
diff --git a/libc/stdio/fread.c b/libc/stdio/fread.c
index bac8dad..f3f0127 100644
--- a/libc/stdio/fread.c
+++ b/libc/stdio/fread.c
@@ -102,6 +102,12 @@
 		 * avoid copying it through the buffer?
 		 */
 		if (total > (size_t) fp->_bf._size) {
+			/*
+			 * Make sure that fseek doesn't think it can
+			 * reuse the buffer since we are going to read
+			 * directly from the file descriptor.
+			 */
+			fp->_flags |= __SMOD;
 			break;
 		}