nano: needs wchar

Fixes:
http://autobuild.buildroot.net/results/317/3177b7d6168eec0620e4a1ade9166c9c84929e6e/

[Peter: add comment when not available]
Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/nano/Config.in

@@ -1,5 +1,6 @@
 config BR2_PACKAGE_NANO
 	bool "nano"
+	depends on BR2_USE_WCHAR
 	# full version uses fork()
 	select BR2_PACKAGE_NANO_TINY if !BR2_USE_MMU
 	select BR2_PACKAGE_NCURSES
@@ -15,3 +16,6 @@ config BR2_PACKAGE_NANO_TINY
 	depends on BR2_PACKAGE_NANO
 	help
 	  Disable all features for the sake of size.
+
+comment "nano needs a toolchain w/ wchar"
+	depends on !BR2_USE_WCHAR