package/frotz: needs threads

Fixes:
 - http://autobuild.buildroot.org/results/8443316d8074bf44a82ceeda4630a9acb1254947

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/frotz/Config.in

@@ -1,5 +1,6 @@
 config BR2_PACKAGE_FROTZ
 	bool "frotz"
+	depends on BR2_TOOLCHAIN_HAS_THREADS
 	select BR2_PACKAGE_NCURSES
 	help
 	  Frotz is an interpreter for old Infocom adventure games and
@@ -8,3 +9,6 @@ config BR2_PACKAGE_FROTZ
 	  be able to use it.
 
 	  https://661.org/proj/if/frotz/
+
+comment "frotz needs a toolchain w/ threads"
+	depends on !BR2_TOOLCHAIN_HAS_THREADS