Fixed compile on OpenBSD (#3085)

cmake/LibraryConfigurations.cmake

@@ -25,6 +25,18 @@ if (${PLATFORM} MATCHES "Desktop")
         add_definitions(-D_CRT_SECURE_NO_WARNINGS)
         find_package(OpenGL QUIET)
         set(LIBS_PRIVATE ${OPENGL_LIBRARIES} winmm)
+    elseif (UNIX)
+        find_library(pthread NAMES pthread)
+        find_package(OpenGL QUIET)
+        if ("${OPENGL_LIBRARIES}" STREQUAL "")
+            set(OPENGL_LIBRARIES "GL")
+        endif ()
+
+        if ("${CMAKE_SYSTEM_NAME}" MATCHES "(Net|Open)BSD")
+            find_library(OSS_LIBRARY ossaudio)
+        endif ()
+
+        set(LIBS_PRIVATE m pthread ${OPENGL_LIBRARIES} ${OSS_LIBRARY})
     else ()
         find_library(pthread NAMES pthread)
         find_package(OpenGL QUIET)