added support for pkgconfig

cmake/PROJECT_NAME.pc.in.in

+Name: @PROJECT_NAME@
+Description: Config for @PROJECT_NAME@
+Version: @@PROJECT_NAME@_SOVERSION@
+Cflags: @@PROJECT_NAME@_CXX_FLAGS_MAKEFILE@
+Libs: @@PROJECT_NAME@_LINKER_FLAGS_MAKEFILE@

cmake/create_cmake_config_files.cmake

@@ -27,7 +27,7 @@
 #
 #######################################################################################################################
 
-# create variables for standard makefiles
+# create variables for standard makefiles and pkgconfig
 set(${PROJECT_NAME}_CXX_FLAGS_MAKEFILE "${${PROJECT_NAME}_CXX_FLAGS}")
 
 string(REPLACE " " ";" LIST "${${PROJECT_NAME}_INCLUDE_DIRS}")
@@ -79,6 +79,11 @@ configure_file(${PROJECT_BINARY_DIR}/cmake/${PROJECT_NAME}ConfigVersion.cmake.in
 configure_file(cmake/PROJECT_NAME-config.in.in "${PROJECT_BINARY_DIR}/cmake/${PROJECT_NAME}-config.in" @ONLY)
 configure_file(${PROJECT_BINARY_DIR}/cmake/${PROJECT_NAME}-config.in "${PROJECT_BINARY_DIR}/${PROJECT_NAME}-config" @ONLY)
 
+# create the pkgconfig file
+configure_file(cmake/PROJECT_NAME.pc.in.in "${PROJECT_BINARY_DIR}/cmake/${PROJECT_NAME}.pc.in" @ONLY)
+configure_file(${PROJECT_BINARY_DIR}/cmake/${PROJECT_NAME}.pc.in "${PROJECT_BINARY_DIR}/${PROJECT_NAME}.pc" @ONLY)
+
+
 # install cmake find_package configuration file
 install(FILES "${PROJECT_BINARY_DIR}/${PROJECT_NAME}Config.cmake"
   DESTINATION lib/cmake/${PROJECT_NAME} COMPONENT dev)
@@ -92,3 +97,5 @@ install(FILES "${PROJECT_BINARY_DIR}/${PROJECT_NAME}Config.cmake"
 # install script for Makefiles
 install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}-config DESTINATION bin COMPONENT dev)
 
+# install configuration file for pkgconfig
+install(FILES "${PROJECT_BINARY_DIR}/${PROJECT_NAME}.pc" DESTINATION share/pkgconfig COMPONENT dev)