diff --git a/package/exim/Config.in b/package/exim/Config.in
index bd4ef1fa84..230ac86f96 100644
--- a/package/exim/Config.in
+++ b/package/exim/Config.in
@@ -1,6 +1,10 @@
+comment "exim needs a toolchain w/ threads"
+	depends on !BR2_TOOLCHAIN_HAS_THREADS
+
 config BR2_PACKAGE_EXIM
 	bool "exim"
 	depends on BR2_USE_MMU # fork()
+	depends on BR2_TOOLCHAIN_HAS_THREADS
 	select BR2_PACKAGE_PCRE
 	select BR2_PACKAGE_BERKELEYDB
 	help