build: fix building under windows with thread support

Fixes: 972289f3 ("Detect existence of pthread_mutexattr_setprotocol()")

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 014044cb45951f0ca65d0fa22972c97b37a2582c..93f66830bc43cac03ce17ffc2ed83b2be893e4a4 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -831,7 +831,7 @@ set(HDR_PUBLIC
     include/event2/visibility.h
     ${PROJECT_BINARY_DIR}/include/event2/event-config.h)
 
-set(SRC_CORE
+list(APPEND SRC_CORE
     buffer.c
     bufferevent.c
     bufferevent_filter.c