From b1d05c1f94dc45f7414bcd4c27ba49c86abbedb7 Mon Sep 17 00:00:00 2001
From: Lectem <lectem@gmail.com>
Date: Wed, 5 Feb 2020 01:07:17 +0100
Subject: [PATCH] CMake package should add the modules to CMAKE_MODULE_PATH

Right now aws-c-event-stream needs a lot of boilerplate code to determine the modules installation path while the aws-c-common package should provide it.
This would fix https://github.com/awslabs/aws-c-event-stream/issues/15 simply by moving `find_package(aws-c-common REQUIRED)` before the various module `include`s
Using `configure_package_config_file` makes it easier to have a relocatable package.
---
 CMakeLists.txt                  | 14 +++++++++++---
 cmake/aws-c-common-config.cmake |  4 ++++
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1502eba78..353a4828f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -27,6 +27,7 @@ include(AwsSharedLibSetup)
 include(AwsFeatureTests)
 include(AwsSanitizers)
 include(AwsSIMD)
+include(CMakePackageConfigHelpers)
 include(CTest)
 
 set(GENERATED_ROOT_DIR "${CMAKE_CURRENT_BINARY_DIR}/generated")
@@ -195,9 +196,16 @@ endforeach()
 
 aws_prepare_shared_lib_exports(${PROJECT_NAME})
 
-configure_file("cmake/${PROJECT_NAME}-config.cmake"
+set(AWS_MODULE_INSTALL_DIR "${LIBRARY_DIRECTORY}/cmake")
+
+configure_package_config_file(
+  "cmake/${PROJECT_NAME}-config.cmake"
   "${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}-config.cmake"
-  @ONLY)
+  INSTALL_DESTINATION "${LIBRARY_DIRECTORY}/${PROJECT_NAME}/cmake"
+  PATH_VARS AWS_MODULE_INSTALL_DIR
+  # Imported targets do not require the following macros
+  NO_SET_AND_CHECK_MACRO
+  NO_CHECK_REQUIRED_COMPONENTS_MACRO)
 
 if (BUILD_SHARED_LIBS)
    set (TARGET_DIR "shared")
@@ -226,7 +234,7 @@ list(APPEND EXPORT_MODULES
     )
 
 install(FILES ${EXPORT_MODULES}
-        DESTINATION "${LIBRARY_DIRECTORY}/cmake"
+        DESTINATION "${AWS_MODULE_INSTALL_DIR}"
         COMPONENT Development)
 
 # This should come last, to ensure all variables defined by cmake will be available for export
diff --git a/cmake/aws-c-common-config.cmake b/cmake/aws-c-common-config.cmake
index 0c138ef4c..e867394ae 100644
--- a/cmake/aws-c-common-config.cmake
+++ b/cmake/aws-c-common-config.cmake
@@ -1,3 +1,7 @@
+@PACKAGE_INIT@
+
+list(APPEND CMAKE_MODULE_PATH "@AWS_MODULE_INSTALL_DIR@")
+
 set(THREADS_PREFER_PTHREAD_FLAG ON)
 find_package(Threads REQUIRED)