cmake: install flatcc-config-version.cmake to allow version discrimination when using find_package

Author: madebr

CMakeLists.txt

@@ -352,12 +352,24 @@ if (FLATCC_INSTALL)
     install(DIRECTORY include/flatcc DESTINATION include)
     install(EXPORT flatcc_exports NAMESPACE flatcc:: DESTINATION ${lib_dir}/cmake/flatcc FILE flatcc-targets.cmake)
 
+    file(READ include/flatcc/flatcc_version.h FLATCC_VERSION_H_CONTENT)
+    string(REGEX MATCH "#[ \t]*define[ \t]+FLATCC_VERSION_TEXT[ \t]+\"([^\"]+)\"" version_match "${FLATCC_VERSION_H_CONTENT}")
+    if(NOT version_match)
+        message(FATAL_ERROR "Could not parse the version from include/flatcc/flatcc_version.h")
+    endif()
+    set(FLATCC_VERSION "${CMAKE_MATCH_1}")
+    message(VERBOSE "Extracted version from include/flatcc/flatcc_version.h: ${FLATCC_VERSION}")
+
     include(CMakePackageConfigHelpers)
     configure_package_config_file(cmake/flatcc-config.cmake.in flatcc-config.cmake
         INSTALL_DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/flatcc")
+    write_basic_package_version_file(flatcc-config-version.cmake
+        VERSION "${FLATCC_VERSION}"
+        COMPATIBILITY AnyNewerVersion)
     install(
         FILES
             "${CMAKE_CURRENT_BINARY_DIR}/flatcc-config.cmake"
+            "${CMAKE_CURRENT_BINARY_DIR}/flatcc-config-version.cmake"
             cmake/FlatccGenerateSources.cmake
         DESTINATION "lib/cmake/flatcc")
 endif()