Added packaging using CPack and generation of pkg-config files.

Fixed installation directory - the lib is architecture-independent and so CMake and pkg-config files should go into <prefix>/lib, not into <prefix>/lib/<arch>

CMakeLists.txt

@@ -1,13 +1,21 @@
 cmake_minimum_required(VERSION 3.8)
+
 project(argparse VERSION 1.0.0 LANGUAGES CXX)
+set("PROJECT_DESCRIPTION" "A single header argument parser for C++17")
+set("PROJECT_HOMEPAGE_URL" "https://github.com/p-ranav/argparse")
+
 option(ARGPARSE_BUILD_TESTS OFF)
 option(ARGPARSE_LONG_VERSION_ARG_ONLY OFF)
 
 include(GNUInstallDirs)
+include(CMakePackageConfigHelpers)
+string(REPLACE "/${CMAKE_LIBRARY_ARCHITECTURE}" "" CMAKE_INSTALL_LIBDIR_ARCHIND "${CMAKE_INSTALL_LIBDIR}")
+
 
 add_library(argparse INTERFACE)
 add_library(argparse::argparse ALIAS argparse)
 
+
 if (ARGPARSE_LONG_VERSION_ARG_ONLY)
 	target_compile_definitions(argparse INTERFACE ARGPARSE_LONG_VERSION_ARG_ONLY=true)
 endif ()
@@ -17,16 +25,72 @@ target_include_directories(argparse INTERFACE
   $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
   $<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/include>)
 
+
 if(ARGPARSE_BUILD_TESTS)
   add_subdirectory(test)
 endif()
 
+if(${CMAKE_VERSION} VERSION_GREATER "3.14")
+    set(OPTIONAL_ARCH_INDEPENDENT "ARCH_INDEPENDENT")
+endif()
+
 install(TARGETS argparse EXPORT argparseConfig)
 install(EXPORT argparseConfig
         NAMESPACE argparse::
-        DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/argparse)
+        DESTINATION ${CMAKE_INSTALL_LIBDIR_ARCHIND}/cmake/${PROJECT_NAME})
 install(FILES ${CMAKE_CURRENT_LIST_DIR}/include/argparse/argparse.hpp
         DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/argparse)
 
+
+set(CONFIG_FILE_NAME_WITHOUT_EXT "${PROJECT_NAME}Config")
+set(CMAKE_CONFIG_FILE_BASENAME "${CMAKE_CURRENT_BINARY_DIR}/${CONFIG_FILE_NAME_WITHOUT_EXT}")
+set(CMAKE_CONFIG_VERSION_FILE_NAME "${CMAKE_CONFIG_FILE_BASENAME}-version.cmake")
+set(CMAKE_CONFIG_FILE_NAME "${CMAKE_CONFIG_FILE_BASENAME}.cmake")
+
+if(${CMAKE_VERSION} VERSION_GREATER "3.14")
+	set(OPTIONAL_ARCH_INDEPENDENT "ARCH_INDEPENDENT")
+endif()
+
+write_basic_package_version_file("${CMAKE_CONFIG_VERSION_FILE_NAME}"
+    COMPATIBILITY ExactVersion
+    ${OPTIONAL_ARCH_INDEPENDENT}
+)
+
 export(EXPORT argparseConfig
        NAMESPACE argparse::)
+
+install(FILES "${CMAKE_CONFIG_VERSION_FILE_NAME}"
+       DESTINATION "${CMAKE_INSTALL_LIBDIR_ARCHIND}/cmake/${PROJECT_NAME}")
+
+set(PackagingTemplatesDir "${CMAKE_CURRENT_SOURCE_DIR}/packaging")
+
+set(CPACK_PACKAGE_NAME "${PROJECT_NAME}")
+set(CPACK_PACKAGE_VENDOR "argparse (C++) developers")
+set(CPACK_PACKAGE_DESCRIPTION "${PROJECT_DESCRIPTION}")
+set(CPACK_DEBIAN_PACKAGE_NAME "${CPACK_PACKAGE_NAME}")
+set(CPACK_RPM_PACKAGE_NAME "${CPACK_PACKAGE_NAME}")
+set(CPACK_PACKAGE_HOMEPAGE_URL "${PROJECT_HOMEPAGE_URL}")
+set(CPACK_PACKAGE_MAINTAINER "Pranav Srinivas Kumar")
+set(CPACK_DEBIAN_PACKAGE_MAINTAINER "${CPACK_PACKAGE_MAINTAINER}")
+set(CPACK_RESOURCE_FILE_LICENSE "${CMAKE_CURRENT_SOURCE_DIR}/LICENSE")
+set(CPACK_RESOURCE_FILE_README "${CMAKE_CURRENT_SOURCE_DIR}/README.md")
+
+set(CPACK_DEBIAN_PACKAGE_NAME "lib${PROJECT_NAME}-dev")
+set(CPACK_DEBIAN_PACKAGE_DEPENDS "libc6-dev")
+set(CPACK_DEBIAN_PACKAGE_SUGGESTS "cmake, pkg-config, pkg-conf")
+
+set(CPACK_RPM_PACKAGE_NAME "lib${PROJECT_NAME}-devel")
+set(CPACK_RPM_PACKAGE_SUGGESTS "${CPACK_DEBIAN_PACKAGE_SUGGESTS}")
+
+set(CPACK_DEB_COMPONENT_INSTALL ON)
+set(CPACK_RPM_COMPONENT_INSTALL ON)
+set(CPACK_NSIS_COMPONENT_INSTALL ON)
+set(CPACK_DEBIAN_COMPRESSION_TYPE "xz")
+
+set(PKG_CONFIG_FILE_NAME "${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}.pc")
+configure_file("${PackagingTemplatesDir}/pkgconfig.pc.in" "${PKG_CONFIG_FILE_NAME}" @ONLY)
+install(FILES "${PKG_CONFIG_FILE_NAME}"
+        DESTINATION "${CMAKE_INSTALL_LIBDIR_ARCHIND}/pkgconfig"
+)
+
+include(CPack)

packaging/pkgconfig.pc.in

@@ -0,0 +1,7 @@
+prefix=@CMAKE_INSTALL_PREFIX@
+includedir=${prefix}/@CMAKE_INSTALL_INCLUDEDIR@
+
+Name: @PROJECT_NAME@
+Description: @PROJECT_DESCRIPTION@
+Version: @PROJECT_VERSION@
+Cflags: -I${includedir}