CMake: Improve config installation

Use 'GNUInstallDirs' standard module to set destinations of installed
files.

Use uppercase "CURL" names instead of lowercase "curl" to match standard
'FindCURL.cmake' CMake module:
* https://cmake.org/cmake/help/latest/module/FindCURL.html

Meaning:
* Install 'CURLConfig.cmake' instead of 'curl-config.cmake'
* User should call 'find_package(CURL)' instead of 'find_package(curl)'

Use 'configure_package_config_file' function to generate
'CURLConfig.cmake' file. This will make 'curl-config.cmake.in' template
file smaller and handle components better.  E.g.  current configuration
report no error if user specified unknown components (note: new
configuration expects no components, report error if user will try to
specify any).

Closes https://github.com/curl/curl/pull/2849

1 files changed, 3 insertions, 58 deletions

diff --git a/CMake/curl-config.cmake.in b/CMake/curl-config.cmake.in
index 40c1288e1..2cae644c0 100644
--- a/CMake/curl-config.cmake.in
+++ b/CMake/curl-config.cmake.in
@@ -1,64 +1,9 @@
-
-get_filename_component(_DIR "${CMAKE_CURRENT_LIST_FILE}" PATH)
-
-if(NOT CURL_FIND_COMPONENTS)
-  set(CURL_FIND_COMPONENTS curl libcurl)
-  if(CURL_FIND_REQUIRED)
-    set(CURL_FIND_REQUIRED_curl TRUE)
-    set(CURL_FIND_REQUIRED_libcurl TRUE)
-  endif()
-endif()
+@PACKAGE_INIT@
 
 if("@USE_OPENSSL@")
     include(CMakeFindDependencyMacro)
     find_dependency(OpenSSL "@OPENSSL_VERSION_MAJOR@")
 endif()
 
-set(_curl_missing_components)
-foreach(_comp ${CURL_FIND_COMPONENTS})
-  if(EXISTS "${_DIR}/${_comp}-target.cmake")
-    include("${_DIR}/${_comp}-target.cmake")
-    set(CURL_${_comp}_FOUND TRUE)
-  else()
-    set(CURL_${_comp}_FOUND FALSE)
-    if(CURL_FIND_REQUIRED_${_comp})
-      set(CURL_FOUND FALSE)
-      list(APPEND _curl_missing_components ${_comp})
-    endif()
-  endif()
-endforeach()
-
-if(_curl_missing_components)
-  set(CURL_NOT_FOUND_MESSAGE "Following required components not found: " ${_curl_missing_components})
-else()
-  if(TARGET CURL::libcurl)
-    string(TOUPPER "${CMAKE_BUILD_TYPE}" _curl_current_config)
-    if(NOT _curl_current_config)
-      set(_curl_current_config "NOCONFIG")
-    endif()
-    get_target_property(_curl_configurations CURL::libcurl IMPORTED_CONFIGURATIONS)
-    list(FIND _curl_configurations "${_curl_current_config}" _i)
-    if(_i LESS 0)
-      set(_curl_config "RELEASE")
-      list(FIND _curl_configurations "${_curl_current_config}" _i)
-      if(_i LESS 0)
-        set(_curl_config "NOCONFIG")
-        list(FIND _curl_configurations "${_curl_current_config}" _i)
-      endif()
-    endif()
-
-    if(_i LESS 0)
-      set(_curl_current_config "") # let CMake pick config at random
-    else()
-      set(_curl_current_config "_${_curl_current_config}")
-    endif()
-
-    get_target_property(CURL_INCLUDE_DIRS CURL::libcurl INTERFACE_INCLUDE_DIRECTORIES)
-    get_target_property(CURL_LIBRARIES CURL::libcurl "LOCATION${_curl_current_config}")
-    set(_curl_current_config)
-    set(_curl_configurations)
-    set(_i)
-  endif()
-endif()
-
-unset(_curl_missing_components)
+include("${CMAKE_CURRENT_LIST_DIR}/@TARGETS_EXPORT_NAME@.cmake")
+check_required_components("@PROJECT_NAME@")