various warning/errorwarning fixes for gcc47

. warnings (sometimes promoted to errors) in servers/ and kernel/
 . -Os for ext2 boot module to make it small enough

kernel/arch/i386/direct_tty_utils.c

@@ -122,7 +122,7 @@ void direct_print(const char *str)
 
 int direct_read_char(unsigned char *ch)
 {
-	unsigned long b, sb;
+	unsigned long sb;
 
 	sb = inb(KB_STATUS);
 
@@ -130,7 +130,7 @@ int direct_read_char(unsigned char *ch)
 		return 0;
 	}
 
-	b = inb(KEYBD);
+	inb(KEYBD);
 
 	if (!(sb & KB_AUX_BYTE))
 		return 1;

kernel/arch/i386/memory.c

@@ -560,7 +560,6 @@ static void vm_print(u32_t *root)
 int vm_memset(endpoint_t who, phys_bytes ph, const u8_t c, phys_bytes bytes)
 {
 	u32_t p;
-	int r = OK;
 	struct proc *whoptr = NULL;
 	
 	/* NONE for physical, otherwise virtual */
@@ -592,7 +591,6 @@ int vm_memset(endpoint_t who, phys_bytes ph, const u8_t c, phys_bytes bytes)
 		 */
 		if((pfa=phys_memset(ptr, p, chunk))) {
 			printf("kernel memset pagefault\n");
-			r = EFAULT;
 			break;
 		}
 		bytes -= chunk;

kernel/proc.c

@@ -1168,7 +1168,6 @@ int try_deliver_senda(struct proc *caller_ptr,
   for (i = 0; i < size; i++) {
 	/* Process each entry in the table and store the result in the table.
 	 * If we're done handling a message, copy the result to the sender. */
-  	int pending_recv = FALSE;
 
 	dst = NONE;
 	/* Copy message to kernel */
@@ -1220,7 +1219,6 @@ int try_deliver_senda(struct proc *caller_ptr,
 		/* Inform receiver that something is pending */
 		set_sys_bit(priv(dst_ptr)->s_asyn_pending, 
 			    priv(caller_ptr)->s_id); 
-		pending_recv = TRUE;
 		done = FALSE;
 		continue;
 	}