diff --git a/engine/common/sys_linux_threads.c b/engine/common/sys_linux_threads.c
index 31e32c5be..fb2b45b28 100644
--- a/engine/common/sys_linux_threads.c
+++ b/engine/common/sys_linux_threads.c
@@ -38,7 +38,7 @@ static qboolean Sys_IsThread(void *thread)
 {
 	return pthread_equal(pthread_self(), *(pthread_t*)thread);
 }
-boolean Sys_IsMainThread(void)
+qboolean Sys_IsMainThread(void)
 {
 	return Sys_IsThread(&mainthread);
 }