Fix issues from discussion.

CMakeLists.txt

@@ -10,10 +10,6 @@ set(CMAKE_CXX_STANDARD 14)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)
 
-#pkg-config values
-set(DXHEADERS_URL "https://github.com/microsoft/DirectX-Headers")
-set(DXHEADERS_DESCRIPTION "Headers for using D3D12")
-
 # It's useful to know if you are a top level project or not, if your project is
 # being consumed via add_subdirectory
 if(CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME)
@@ -93,13 +89,14 @@ if (DXHEADERS_INSTALL)
             DESTINATION ${CMAKE_INSTALL_DATAROOTDIR}/directx-headers/cmake)
     
     # Create pkg-config file 
-    set(DIRECTX_HEADERS_L DirectX-Headers)
-    set(DIRECTX_GUIDS_L DirectX-Guids)
-         
+    include(cmake/JoinPaths.cmake)
+    # from: https://github.com/jtojnar/cmake-snips#concatenating-paths-when-building-pkg-config-files
+    join_paths(DIRECTX_INCLUDEDIR_FOR_PKG_CONFIG "\${prefix}" "${CMAKE_INSTALL_INCLUDEDIR}")
+    join_paths(DIRECTX_LIBDIR_FOR_PKG_CONFIG "\${prefix}"     "${CMAKE_INSTALL_LIBDIR}")        
     configure_file(
         "${CMAKE_CURRENT_SOURCE_DIR}/cmake/DirectX-Headers.pc.in"
         "${CMAKE_CURRENT_BINARY_DIR}/DirectX-Headers.pc" @ONLY)
-        
+
     # Install the pkg-config file
     install(FILES "${CMAKE_CURRENT_BINARY_DIR}/DirectX-Headers.pc"
             DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)

cmake/DirectX-Headers.pc.in

@@ -1,11 +1,10 @@
-prefix="@CMAKE_INSTALL_PREFIX@"
-exec_prefix="${prefix}"
-libdir="${prefix}/lib"
-includedir="${prefix}/include"
+prefix=@CMAKE_INSTALL_PREFIX@
+libdir=@DIRECTX_LIBDIR_FOR_PKG_CONFIG@
+includedir=@DIRECTX_INCLUDEDIR_FOR_PKG_CONFIG@
 
 Name: @PROJECT_NAME@
-Description: @DXHEADERS_DESCRIPTION@
-URL: @DXHEADERS_URL@
+Description: Headers for using D3D12
+URL: https://github.com/microsoft/DirectX-Header
 Version: @PROJECT_VERSION@
 Cflags: -I${includedir}
-Libs: -l@DIRECTX_HEADERS_L@ -l@DIRECTX_GUIDS_L@
+Libs: -lDirectX-Headers -lDirectX-Guids

cmake/JoinPaths.cmake

@@ -0,0 +1,23 @@
+# This module provides function for joining paths
+# known from most languages
+#
+# SPDX-License-Identifier: (MIT OR CC0-1.0)
+# Copyright 2020 Jan Tojnar
+# https://github.com/jtojnar/cmake-snips
+#
+# Modelled after Python’s os.path.join
+# https://docs.python.org/3.7/library/os.path.html#os.path.join
+# Windows not supported
+function(join_paths joined_path first_path_segment)
+    set(temp_path "${first_path_segment}")
+    foreach(current_segment IN LISTS ARGN)
+        if(NOT ("${current_segment}" STREQUAL ""))
+            if(IS_ABSOLUTE "${current_segment}")
+                set(temp_path "${current_segment}")
+            else()
+                set(temp_path "${temp_path}/${current_segment}")
+            endif()
+        endif()
+    endforeach()
+    set(${joined_path} "${temp_path}" PARENT_SCOPE)
+endfunction()