Index: Source/WTF/wtf/PlatformGTK.cmake
--- Source/WTF/wtf/PlatformGTK.cmake.orig
+++ Source/WTF/wtf/PlatformGTK.cmake
@@ -72,6 +72,12 @@ elseif (CMAKE_SYSTEM_NAME MATCHES "FreeBSD" OR CMAKE_S
 
         unix/MemoryPressureHandlerUnix.cpp
     )
+elseif (CMAKE_SYSTEM_NAME MATCHES "OpenBSD")
+    list(APPEND WTF_SOURCES
+        generic/MemoryFootprintGeneric.cpp
+
+        unix/MemoryPressureHandlerUnix.cpp
+    )
 else ()
     list(APPEND WTF_SOURCES
         generic/MemoryFootprintGeneric.cpp
