build: add cmark-gfm-config to allow wiring up builds

Enable wiring up builds with the staged image of cmark. The unified
build no longer tries to use custom build handling and instead prefers
the standard CMake usage.

CMakeLists.txt

@@ -109,6 +109,11 @@ if(CMARK_FUZZ_QUADRATIC)
   add_subdirectory(fuzz)
 endif()
 
-export(TARGETS libcmark-gfm libcmark-gfm-extensions
-  FILE cmark-gfmConfig.cmake)
+include(CMakePackageConfigHelpers)
+configure_package_config_file(cmark-gfm-config.cmake.in
+  ${CMAKE_BINARY_DIR}/cmake/modules/cmark-gfm-config.cmake
+  INSTALL_DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake)
+install(FILES
+  ${CMAKE_BINARY_DIR}/cmake/modules/cmark-gfm-config.cmake
+  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake)
 

cmark-gfm-config.cmake.in

@@ -0,0 +1,3 @@
+@PACKAGE_INIT@
+include(${CMAKE_CURRENT_LIST_DIR}/cmark-gfm/cmark-gfm.cmake)
+include(${CMAKE_CURRENT_LIST_DIR}/cmark-gfm-extensions/cmark-gfm-extensions.cmake)

extensions/CMakeLists.txt

@@ -33,4 +33,4 @@ install(FILES
   include/module.modulemap
   DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/cmark_gfm_extensions)
 install(EXPORT cmark-gfm-extensions
-  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake-gfm-extensions)
+  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/cmark-gfm-extensions)

src/CMakeLists.txt

@@ -90,7 +90,7 @@ install(FILES
 install(FILES ${CMAKE_CURRENT_BINARY_DIR}/libcmark-gfm.pc
   DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
 install(EXPORT cmark-gfm
-  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake)
+  DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/cmark-gfm)
 
 export(TARGETS libcmark-gfm
   FILE ${CMAKE_CURRENT_BINARY_DIR}/cmarkTargets.cmake)