firmware: Enable -Wformat and resolve all related compiler warnings
There have been tons of format-string related bugs in our code which
we never discovered due to disabling -Wformat. Let's fix that.
Change-Id: I5ec466361bcc526fac1f4897673264ee5af3458b
diff --git a/firmware/libcommon/source/stdio.c b/firmware/libcommon/source/stdio.c
index 06ad611..04d73f0 100644
--- a/firmware/libcommon/source/stdio.c
+++ b/firmware/libcommon/source/stdio.c
@@ -62,8 +62,10 @@
//------------------------------------------------------------------------------
//
FILE* const stdin = NULL;
-FILE* const stdout = NULL;
-FILE* const stderr = NULL;
+/* If we use NULL here, we get compiler warnings of calling stdio functions with
+ * NULL values. Our fputs() implementation ignores the value of those pointers anyway */
+FILE* const stdout = (FILE *) 0x1;
+FILE* const stderr = (FILE *) 0x2;
//------------------------------------------------------------------------------