libobs: Add currently used Qt version to obsconfig.h.in

Allows the ability to have code depending on whether OBS is being
compiled with Qt5 or Qt6

libobs/CMakeLists.txt

@@ -11,6 +11,12 @@ find_package(
   OPTIONAL_COMPONENTS avcodec)
 find_package(ZLIB REQUIRED)
 
+if(ENABLE_UI)
+  find_qt(COMPONENTS Core)
+else()
+  set(_QT_VERSION 0)
+endif()
+
 add_library(libobs SHARED)
 add_library(OBS::libobs ALIAS libobs)
 

libobs/obsconfig.h.in

@@ -14,6 +14,7 @@
 #define OBS_DATA_PATH "@OBS_DATA_PATH@"
 #define OBS_INSTALL_PREFIX "@OBS_INSTALL_PREFIX@"
 #define OBS_PLUGIN_DESTINATION "@OBS_PLUGIN_DESTINATION@"
+#define OBS_QT_VERSION @_QT_VERSION@
 
 #cmakedefine LINUX_PORTABLE
 #cmakedefine GIO_FOUND