include: Changes to avoid warnings during compilation

Changes to suppress warnings for enabling Werror flag in LK

Change-Id: I2e5007cfcb7fa75c04b8696efd794bdc6da47ecf
diff --git a/include/stdio.h b/include/stdio.h
index ebabfca..5052636 100644
--- a/include/stdio.h
+++ b/include/stdio.h
@@ -4,9 +4,21 @@
 #include <debug.h>
 #include <printf.h>
 
+typedef struct {
+	char *fpos; /* Current position of file pointer (absolute address) */
+	void *base; /* Pointer to the base of the file */
+	unsigned short handle; /* File handle */
+	short flags; /* Flags (see FileFlags) */
+	short unget; /* 1-byte buffer for ungetc (b15=1 if non-empty) */
+	unsigned long alloc; /* Number of currently allocated bytes for the file */
+	unsigned short buffincrement; /* Number of bytes allocated at once */
+} FILE;
+
 void putc(char c);
 int puts(const char *str);
 int getc(char *c); // XXX not really getc
+size_t fwrite(const void *buf, size_t size, size_t count, FILE *stream);
+int sscanf(const char *str, const char *format, ...);
 
 #endif