Drop newlib printf: log via BDK s_vprintf, add debug.ini log switch

log_write was the only vsnprintf user and pulled in newlib's printf,
dtoa, malloc and soft-float code (~44 KB). The payload now fits the
RCM limit again (146800 -> 102801 bytes); the build fails if it grows
past it. debug.ini log=1 writes sd:/config/omninx/install.log.

bdk/utils/sprintf.h

@@ -1,24 +1,26 @@
-/*
- * Copyright (c) 2019-2020 shchmue
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms and conditions of the GNU General Public License,
- * version 2, as published by the Free Software Foundation.
- *
- * This program is distributed in the hope it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
- * more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#ifndef _SPRINTF_H_
-#define _SPRINTF_H_
-
-#include "types.h"
-
-u32 s_printf(char *buffer, const char *fmt, ...);
-
-#endif
+/*
+ * Copyright (c) 2019-2020 shchmue
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _SPRINTF_H_
+#define _SPRINTF_H_
+
+#include "types.h"
+#include <stdarg.h>
+
+u32 s_printf(char *buffer, const char *fmt, ...);
+u32 s_vprintf(char *buffer, const char *fmt, va_list ap);
+
+#endif