cmake: set readonly permissions on install

CMakeLists.txt

@@ -14,5 +14,6 @@ install(
     FILES
     "cmake/xo_cxx.cmake"
     "cmake/code-coverage.cmake"
+    PERMISSIONS OWNER_READ GROUP_READ WORLD_READ
     DESTINATION share/cmake/${XO_PROJECT_NAME}
 )

cmake/xo_cxx.cmake

@@ -167,6 +167,7 @@ endmacro()
 macro(xo_install_include_tree)
     install(
         DIRECTORY ${PROJECT_SOURCE_DIR}/include/
+        FILE_PERMISSIONS OWNER_READ GROUP_READ WORLD_READ
         DESTINATION ${CMAKE_INSTALL_PREFIX}/include)
 endmacro()
 
@@ -224,9 +225,13 @@ macro(xo_export_cmake_config projectname projectversion projecttargets)
     )
     install(
         EXPORT ${projecttargets}
+        PERMISSIONS OWNER_READ GROUP_READ WORLD_READ
+        DESTINATION ${CMAKE_INSTALL_PREFIX}/lib/cmake/${projectname})
+    install(
         FILES
         "${PROJECT_BINARY_DIR}/${projectname}ConfigVersion.cmake"
         "${PROJECT_BINARY_DIR}/${projectname}Config.cmake"
+        PERMISSIONS OWNER_READ GROUP_READ WORLD_READ
         DESTINATION ${CMAKE_INSTALL_PREFIX}/lib/cmake/${projectname}
     )
 endmacro()