C Library: Clean-up buffer selections in Kconfig

libc/Kconfig

@@ -6,16 +6,23 @@
 comment "Standard C Library Options"
 
 config STDIO_DISABLE_BUFFERING
-	bool "Disable I/O Buffering"
+	bool "Disable STDIO Buffering"
 	default n
 	---help---
 		Tiny systems may need to disable all support for I/O buffering in
 		order to minimum footprint.
 
+		NOTE that even if STDIO buffering is enabled, you can still disable
+		buffer by setting CONFIG_STDIO_BUFFER_SIZE=0 or dynamically through
+		the setvbuf() interface.  In these case, however, there is no
+		reduction in code size.  Only setting CONFIG_STDIO_DISABLE_BUFFERING
+		will reduce code size.
+
+if !STDIO_DISABLE_BUFFERING
+
 config STDIO_BUFFER_SIZE
-	int "C STDIO buffer size"
+	int "STDIO buffer size"
 	default 64
-	depends on !STDIO_DISABLE_BUFFERING
 	---help---
 		Size of buffers using within the C buffered I/O interfaces (printf,
 		putchar, fwrite, etc.).  This function sets the initial I/O buffer
@@ -31,6 +38,8 @@ config STDIO_LINEBUFFER
 		sets the initial default behavior of all streams.  The behavior of
 		an individual stream can be changed via setvbuf().
 
+endif # !STDIO_DISABLE_BUFFERING
+
 config NUNGET_CHARS
 	int "Number unget() characters"
 	default 2