diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8e9001fd2..bb1493d43 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -593,39 +593,39 @@ ELSE()
 ENDIF()
 
 IF (OSG_GL1_AVAILABLE)
-    SET(OSG_GL1_FEATURES "true")
+    SET(OSG_GL1_FEATURES 1)
 ELSE()
-    SET(OSG_GL1_FEATURES "false")
+    SET(OSG_GL1_FEATURES 0)
 ENDIF()
 
 IF (OSG_GL2_AVAILABLE)
-    SET(OSG_GL2_FEATURES "true")
+    SET(OSG_GL2_FEATURES 1)
 ELSE()
-    SET(OSG_GL2_FEATURES "false")
+    SET(OSG_GL2_FEATURES 0)
 ENDIF()
 
 IF (OSG_GL3_AVAILABLE)
-    SET(OSG_GL3_FEATURES "true")
+    SET(OSG_GL3_FEATURES 1)
 ELSE()
-    SET(OSG_GL3_FEATURES "false")
+    SET(OSG_GL3_FEATURES 0)
 ENDIF()
 
 IF (OSG_GLES1_AVAILABLE)
-    SET(OSG_GLES1_FEATURES "true")
+    SET(OSG_GLES1_FEATURES 1)
 ELSE()
-    SET(OSG_GLES1_FEATURES "false")
+    SET(OSG_GLES1_FEATURES 0)
 ENDIF()
 
 IF (OSG_GLES2_AVAILABLE)
-    SET(OSG_GLES2_FEATURES "true")
+    SET(OSG_GLES2_FEATURES 1)
 ELSE()
-    SET(OSG_GLES2_FEATURES "false")
+    SET(OSG_GLES2_FEATURES 0)
 ENDIF()
 
 IF (OSG_GLES3_AVAILABLE)
-    SET(OSG_GLES3_FEATURES "true")
+    SET(OSG_GLES3_FEATURES 1)
 ELSE()
-    SET(OSG_GLES3_FEATURES "false")
+    SET(OSG_GLES3_FEATURES 0)
 ENDIF()
 
 IF(ANDROID)