icu: needs wchar support in toolchain as well

package/icu/Config.in

@@ -1,10 +1,11 @@
 config BR2_PACKAGE_ICU
 	bool "icu"
 	depends on BR2_INSTALL_LIBSTDCPP
+	depends on BR2_USE_WCHAR
 	help
 	  International Components for Unicode.
 
 	  http://icu-project.org/
 
-comment "icu requires a toolchain with C++ support enabled"
-	depends on !BR2_INSTALL_LIBSTDCPP
+comment "icu requires a toolchain with C++ support and WCHAR enabled"
+	depends on !BR2_INSTALL_LIBSTDCPP || !BR2_USE_WCHAR