mark Linux-specific configuration options

PLATFORM_LINUX is used as a dependency for applets or features
which require Linux-specific interfaces.

Signed-off-by: Jeremie Koenig <jk@jk.fr.eu.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/coreutils/Config.src b/coreutils/Config.src
index d4c9e05..780b73f 100644
--- a/coreutils/Config.src
+++ b/coreutils/Config.src
@@ -591,6 +591,7 @@
 config STAT
 	bool "stat"
 	default y
+	depends on PLATFORM_LINUX # statfs()
 	help
 	  display file or filesystem status.
 
@@ -606,6 +607,7 @@
 config STTY
 	bool "stty"
 	default y
+	depends on PLATFORM_LINUX
 	help
 	  stty is used to change and print terminal line settings.