Use CMakePackageConfigHelpers for package config file

This makes the CMake package relocatable

packaging/CMakeLists.txt

@@ -20,8 +20,13 @@ License along with this program.  If not, see
 include(CMakePackageConfigHelpers)
 
 if (NOT DEFINED NetlibF2C_INSTALL_CMAKEDIR)
-    set(NetlibF2C_INSTALL_CMAKEDIR "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}"
-        CACHE STRING "Path to Netlib LibF2C CMake files")
+    set(
+        NetlibF2C_INSTALL_CMAKEDIR
+        "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}"
+        CACHE
+        STRING
+        "Path to Netlib LibF2C CMake files"
+    )
 endif ()
 
 if (BUILD_SHARED_LIBS)
@@ -100,10 +105,11 @@ if (DEFINED LoadStaticSharedTargets_SOURCE_DIR)
     cmake_path(APPEND CMAKE_INSTALL_PREFIX "${LoadStaticSharedTargets_INSTALL_CMAKEDIR}" OUTPUT_VARIABLE LoadStaticSharedTargets_DIR)
 endif ()
 
-configure_file(
+configure_package_config_file(
     "NetlibF2CConfig.cmake.in"
     "${CMAKE_CURRENT_BINARY_DIR}/NetlibF2CConfig.cmake"
-    @ONLY
+    INSTALL_DESTINATION "${NetlibF2C_INSTALL_CMAKEDIR}"
+    PATH_VARS LoadStaticSharedTargets_DIR
 )
 
 install(

packaging/NetlibF2CConfig.cmake.in

@@ -23,6 +23,8 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 ]]
 
+@PACKAGE_INIT@
+
 cmake_minimum_required(VERSION @CMAKE_MINIMUM_REQUIRED_VERSION@)
 
 set(CMAKE_MAXIMUM_SUPPORTED_VERSION @CMAKE_MAXIMUM_SUPPORTED_VERSION@)
@@ -31,9 +33,14 @@ set(CMAKE_MAXIMUM_SUPPORTED_VERSION @CMAKE_MAXIMUM_SUPPORTED_VERSION@)
 @HANDLE_POLICIES_SCRIPT@
 # end HANDLE_POLICIES_SCRIPT
 
+set_and_check(
+    LoadStaticSharedTargets_DIR
+    "@PACKAGE_LoadStaticSharedTargets_DIR@"
+)
+
 set(
     LoadStaticSharedTargets_DIR
-    "@LoadStaticSharedTargets_DIR@"
+    "${LoadStaticSharedTargets_DIR}"
     CACHE STRING
     "The directory containing a CMake configuration file for LoadStaticSharedTargets."
 )
@@ -50,3 +57,5 @@ load_static_shared_targets(
     "${CMAKE_CURRENT_LIST_DIR}/NetlibF2C_Targets-executable-shared.cmake"
     "${CMAKE_CURRENT_LIST_DIR}/NetlibF2C_Targets-library-shared.cmake"
 )
+
+check_required_components(NetlibF2C)