Fixed CMake build on 2.8 versions

CMakeLists.txt

@@ -147,37 +147,37 @@ add_subdirectory(test)
 set(GLM_INSTALL_CONFIGDIR "${CMAKE_INSTALL_LIBDIR}/cmake/glm")
 install(DIRECTORY glm DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
 
-include(CMakePackageConfigHelpers)
-write_basic_package_version_file(
-    "${CMAKE_CURRENT_BINARY_DIR}/glmVersion.cmake"
-    VERSION ${GLM_VERSION}
-    COMPATIBILITY AnyNewerVersion
-)
-
-# build tree package config
-configure_file(
-    cmake/glmBuildConfig.cmake.in
-    glmConfig.cmake
-    COPYONLY
-)
-
-# install tree package config
-configure_package_config_file(
-    cmake/glmConfig.cmake.in
-    ${GLM_INSTALL_CONFIGDIR}/glmConfig.cmake
-    INSTALL_DESTINATION ${GLM_INSTALL_CONFIGDIR}
-    PATH_VARS CMAKE_INSTALL_INCLUDEDIR
-    NO_CHECK_REQUIRED_COMPONENTS_MACRO
-)
-
-install(
-    FILES 
-        "${CMAKE_CURRENT_BINARY_DIR}/glmConfig.cmake"
-        "${CMAKE_CURRENT_BINARY_DIR}/glmVersion.cmake"
-    DESTINATION ${GLM_INSTALL_CONFIGDIR}
-)
-
 if (NOT CMAKE_VERSION VERSION_LESS "2.8.12")
+	include(CMakePackageConfigHelpers)
+	write_basic_package_version_file(
+	    "${CMAKE_CURRENT_BINARY_DIR}/glmVersion.cmake"
+	    VERSION ${GLM_VERSION}
+	    COMPATIBILITY AnyNewerVersion
+	)
+
+	# build tree package config
+	configure_file(
+	    cmake/glmBuildConfig.cmake.in
+	    glmConfig.cmake
+	    COPYONLY
+	)
+
+	# install tree package config
+	configure_package_config_file(
+	    cmake/glmConfig.cmake.in
+	    ${GLM_INSTALL_CONFIGDIR}/glmConfig.cmake
+	    INSTALL_DESTINATION ${GLM_INSTALL_CONFIGDIR}
+	    PATH_VARS CMAKE_INSTALL_INCLUDEDIR
+	    NO_CHECK_REQUIRED_COMPONENTS_MACRO
+	)
+
+	install(
+	    FILES 
+	        "${CMAKE_CURRENT_BINARY_DIR}/glmConfig.cmake"
+	        "${CMAKE_CURRENT_BINARY_DIR}/glmVersion.cmake"
+	    DESTINATION ${GLM_INSTALL_CONFIGDIR}
+	)
+
     add_library(glm INTERFACE)
     target_include_directories(glm INTERFACE
         $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>