Disable examples and tests when a subproject

This changes the default value of the GLFW_BUILD_EXAMPLES and
GLFW_BUILD_TESTS CMake options to false when GLFW is being added as
a subdirectory by another CMake project.

If you want the previous behavior, force these options to true before
adding the GLFW subdirectory:

set(GLFW_BUILD_EXAMPLES ON CACHE BOOL "" FORCE)
set(GLFW_BUILD_TESTS ON CACHE BOOL "" FORCE)
add_subdirectory(path/to/glfw)

Doing this is backward compatible with earlier versions of GLFW.

The GLFW_BUILD_DOCS option is left enabled as it also requires Doxygen
to have any effect, is quicker to build and is more likely to be useful
when GLFW is a subproject.

CMakeLists.txt

@@ -10,9 +10,13 @@ endif()
 
 set_property(GLOBAL PROPERTY USE_FOLDERS ON)
 
+if ("${CMAKE_SOURCE_DIR}" STREQUAL "${CMAKE_CURRENT_SOURCE_DIR}")
+    set(GLFW_STANDALONE TRUE)
+endif()
+
 option(BUILD_SHARED_LIBS "Build shared libraries" OFF)
-option(GLFW_BUILD_EXAMPLES "Build the GLFW example programs" ON)
-option(GLFW_BUILD_TESTS "Build the GLFW test programs" ON)
+option(GLFW_BUILD_EXAMPLES "Build the GLFW example programs" GLFW_STANDALONE)
+option(GLFW_BUILD_TESTS "Build the GLFW test programs" GLFW_STANDALONE)
 option(GLFW_BUILD_DOCS "Build the GLFW documentation" ON)
 option(GLFW_INSTALL "Generate installation target" ON)
 option(GLFW_VULKAN_STATIC "Assume the Vulkan loader is linked with the application" OFF)

README.md

@@ -118,6 +118,7 @@ information on what to include when reporting a bug.
 
 ## Changelog
 
+ - Disabled tests and examples by default when built as a CMake subdirectory
  - Bugfix: The CMake config-file package used an absolute path and was not
    relocatable (#1470)
  - [X11] Bugfix: The CMake files did not check for the XInput headers (#1480)

docs/build.dox

@@ -186,18 +186,8 @@ build_link_cmake_package.
 With a few changes to your `CMakeLists.txt` you can have the GLFW source tree
 built along with your application.
 
-When including GLFW as part of your build, you probably don't want to build the
-GLFW tests, examples and documentation.  To disable these, set the corresponding
-cache variables before adding the GLFW source tree.
-
-@code
-set(GLFW_BUILD_DOCS OFF CACHE BOOL "" FORCE)
-set(GLFW_BUILD_TESTS OFF CACHE BOOL "" FORCE)
-set(GLFW_BUILD_EXAMPLES OFF CACHE BOOL "" FORCE)
-@endcode
-
-Then add the root directory of the GLFW source tree to your project.  This
-will add the `glfw` target and the necessary cache variables to your project.
+Add the root directory of the GLFW source tree to your project.  This will add
+the `glfw` target and the necessary cache variables to your project.
 
 @code{.cmake}
 add_subdirectory(path/to/glfw)

docs/compile.dox

@@ -212,11 +212,13 @@ library or as a DLL / shared library / dynamic library.
 
 @anchor GLFW_BUILD_EXAMPLES
 __GLFW_BUILD_EXAMPLES__ determines whether the GLFW examples are built
-along with the library.
+along with the library.  This is enabled by default unless GLFW is being built
+as a sub-project.
 
 @anchor GLFW_BUILD_TESTS
 __GLFW_BUILD_TESTS__ determines whether the GLFW test programs are
-built along with the library.
+built along with the library.  This is enabled by default unless GLFW is being
+built as a sub-project.
 
 @anchor GLFW_BUILD_DOCS
 __GLFW_BUILD_DOCS__ determines whether the GLFW documentation is built along

docs/news.dox

@@ -11,6 +11,20 @@
 
 @subsection caveats_34 Caveats for version 3.4
 
+@subsubsection standalone_34 Tests and examples are disabled when built as a sub-project
+
+GLFW now does not build the tests and examples when it is added as
+a subdirectory of another CMake project.  To enable these, set the @ref
+GLFW_BUILD_TESTS and @ref GLFW_BUILD_EXAMPLES cache variables before adding the
+GLFW subdirectory.
+
+@code{.cmake}
+set(GLFW_BUILD_EXAMPLES ON CACHE BOOL "" FORCE)
+set(GLFW_BUILD_TESTS ON CACHE BOOL "" FORCE)
+add_subdirectory(path/to/glfw)
+@endcode
+
+
 @subsection deprecations_34 Deprecations in version 3.4
 
 @subsection removals_34 Removals in 3.4