QPID-7148 Use more modern CMake install machinery for better QpidConf…

…ig.cmake

Turns out, CMake is happy to generate a lot of the QpidConfig.cmake file for us, see
* https://gitlab.kitware.com/cmake/cmake/-/issues/19560
* https://cmake.org/cmake/help/latest/manual/cmake-packages.7.html#creating-packages
* https://cmake.org/cmake/help/latest/guide/importing-exporting/index.html#exporting-targets
* https://cmake.org/cmake/help/latest/module/CMakePackageConfigHelpers.html#example-generating-package-files
* https://cmake.org/cmake/help/latest/guide/tutorial/Packaging%20Debug%20and%20Release.html

This is analogous change to PROTON-2254 for Qpid Proton.

src/CMakeLists.txt

@@ -855,6 +855,7 @@ set_target_properties (qpidcommon PROPERTIES
                        SOVERSION ${qpidcommon_version_major})
 
 install (TARGETS qpidcommon
+         EXPORT QpidTargets
          RUNTIME DESTINATION ${QPID_INSTALL_BINDIR} COMPONENT ${QPID_COMPONENT_COMMON}
          LIBRARY DESTINATION ${QPID_INSTALL_LIBDIR} COMPONENT ${QPID_COMPONENT_COMMON}
          ARCHIVE DESTINATION ${QPID_INSTALL_LIBDIR} COMPONENT ${QPID_COMPONENT_COMMON})
@@ -880,6 +881,7 @@ set_target_properties (qpidtypes PROPERTIES
                        SOVERSION ${qpidtypes_version_major})
 
 install(TARGETS qpidtypes
+        EXPORT  QpidTargets
         RUNTIME DESTINATION ${QPID_INSTALL_BINDIR} COMPONENT ${QPID_COMPONENT_COMMON}
         LIBRARY DESTINATION ${QPID_INSTALL_LIBDIR} COMPONENT ${QPID_COMPONENT_COMMON}
         ARCHIVE DESTINATION ${QPID_INSTALL_LIBDIR} COMPONENT ${QPID_COMPONENT_COMMON})
@@ -939,6 +941,7 @@ set_target_properties (qpidclient PROPERTIES
                        SOVERSION ${qpidclient_version_major})
 
 install (TARGETS qpidclient
+         EXPORT QpidTargets
          RUNTIME DESTINATION ${QPID_INSTALL_BINDIR} COMPONENT ${QPID_COMPONENT_CLIENT}
          LIBRARY DESTINATION ${QPID_INSTALL_LIBDIR} COMPONENT ${QPID_COMPONENT_CLIENT}
          ARCHIVE DESTINATION ${QPID_INSTALL_LIBDIR} COMPONENT ${QPID_COMPONENT_CLIENT})
@@ -1006,6 +1009,7 @@ set_target_properties (qpidmessaging PROPERTIES
                        VERSION ${qpidmessaging_version}
                        SOVERSION ${qpidmessaging_version_major})
 install (TARGETS qpidmessaging
+         EXPORT  QpidTargets
          RUNTIME DESTINATION ${QPID_INSTALL_BINDIR} COMPONENT ${QPID_COMPONENT_CLIENT}
          LIBRARY DESTINATION ${QPID_INSTALL_LIBDIR} COMPONENT ${QPID_COMPONENT_CLIENT}
          ARCHIVE DESTINATION ${QPID_INSTALL_LIBDIR} COMPONENT ${QPID_COMPONENT_CLIENT})
@@ -1311,11 +1315,25 @@ set(QPIDTYPESLIB ${CMAKE_SHARED_LIBRARY_PREFIX}qpidtypes${CMAKE_SHARED_LIBRARY_S
 set(QPIDTYPESLIBDEBUG ${CMAKE_SHARED_LIBRARY_PREFIX}qpidtypes${CMAKE_DEBUG_POSTFIX}${CMAKE_SHARED_LIBRARY_SUFFIX})
 endif ()
 
-configure_file(QpidConfig.cmake.in ${CMAKE_CURRENT_BINARY_DIR}/QpidConfig.cmake @ONLY)
-configure_file(QpidConfigVersion.cmake.in ${CMAKE_CURRENT_BINARY_DIR}/QpidConfigVersion.cmake @ONLY)
+install(EXPORT QpidTargets
+        FILE QpidTargets.cmake
+        NAMESPACE Qpid::
+        DESTINATION ${QPID_INSTALL_LIBDIR}/cmake/Qpid)
+
+include(CMakePackageConfigHelpers)
+include(WriteBasicConfigVersionFile)
+
+configure_package_config_file(
+        ${CMAKE_CURRENT_SOURCE_DIR}/QpidConfig.cmake.in
+        ${CMAKE_CURRENT_BINARY_DIR}/QpidConfig.cmake
+        PATH_VARS includedir
+        INSTALL_DESTINATION ${QPID_INSTALL_LIBDIR}/cmake/Qpid)
+write_basic_config_version_file(
+        ${CMAKE_CURRENT_BINARY_DIR}/QpidConfigVersion.cmake
+        VERSION ${VERSION}
+        COMPATIBILITY AnyNewerVersion)
 install (FILES
-         ${CMAKE_CURRENT_BINARY_DIR}/QpidConfig.cmake
-         ${CMAKE_CURRENT_BINARY_DIR}/QpidConfigVersion.cmake
-         DESTINATION ${QPID_INSTALL_LIBDIR}/cmake/Qpid
-         COMPONENT ${QPID_COMPONENT_COMMON})
-
+        ${CMAKE_CURRENT_BINARY_DIR}/QpidConfig.cmake
+        ${CMAKE_CURRENT_BINARY_DIR}/QpidConfigVersion.cmake
+        DESTINATION ${QPID_INSTALL_LIBDIR}/cmake/Qpid
+        COMPONENT ${QPID_COMPONENT_COMMON})

src/QpidConfig.cmake.in

@@ -22,17 +22,21 @@
 # Version: @VERSION@
 # URL: http://qpid.apache.org/
 
-set (Qpid_VERSION       @VERSION@)
+@PACKAGE_INIT@
+include("${CMAKE_CURRENT_LIST_DIR}/QpidTargets.cmake")
 
-set (Qpid_INCLUDE_DIRS  @includedir@)
-set (Qpid_LIBRARIES     optimized @libdir@/@QPIDMSGLIB@ @libdir@/@QPIDTYPESLIB@ debug @libdir@/@QPIDMSGLIBDEBUG@ @libdir@/@QPIDTYPESLIBDEBUG@)
+set(Qpid_VERSION @VERSION@)
+
+set_and_check (Qpid_INCLUDE_DIRS @PACKAGE_includedir@)
+set (Qpid_LIBRARIES Qpid::qpidmessaging Qpid::qpidtypes)
 
 # Can't make this compatible with CMake 2.8.12 as Qpid::qpid really is an interface target
-# (because it has multiple libraries). So only allow for later versions of CMake
+#  (because it has multiple libraries). So only allow for later versions of CMake
 if (NOT TARGET Qpid::qpid AND CMAKE_VERSION VERSION_GREATER "3.0")
   add_library(Qpid::qpid INTERFACE IMPORTED)
   target_link_libraries(Qpid::qpid INTERFACE ${Qpid_LIBRARIES})
   target_include_directories(Qpid::qpid INTERFACE ${Qpid_INCLUDE_DIRS})
 endif()
 
 set (Qpid_FOUND True)
+check_required_components(Qpid)