Add pkg-config file. (#642)

This file describes the include and lib location and makes
it possible to use the library in build systems other than
CMake, e.g. in basic Makefiles.

Signed-off-by: Henner Zeller <h.zeller@acm.org>

CMakeLists.txt

@@ -3,6 +3,7 @@ cmake_minimum_required(VERSION 3.11)
 project(ftxui
   LANGUAGES CXX
   VERSION 4.0.0
+  DESCRIPTION "C++ Functional Terminal User Interface."
 )
 
 option(FTXUI_BUILD_DOCS "Set to ON to build docs" ON)

cmake/ftxui_install.cmake

@@ -11,6 +11,7 @@ install(TARGETS screen dom component
 
 install(DIRECTORY include/ftxui DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
 
+# CMake package configuration for easy use of library in CMake
 include(CMakePackageConfigHelpers)
 configure_package_config_file(ftxui-config.cmake.in
   ${CMAKE_CURRENT_BINARY_DIR}/ftxui-config.cmake
@@ -31,3 +32,12 @@ install(EXPORT ftxui-export
   NAMESPACE ftxui::
   DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/ftxui
 )
+
+# pkg-config file for easy use of library in build systems other than CMake
+configure_file(ftxui.pc.in
+  ${CMAKE_CURRENT_BINARY_DIR}/ftxui.pc
+  @ONLY)
+
+install(FILES ${CMAKE_CURRENT_BINARY_DIR}/ftxui.pc
+  DESTINATION lib/pkgconfig
+)

ftxui.pc.in

@@ -0,0 +1,9 @@
+prefix="@CMAKE_INSTALL_PREFIX@"
+libdir="@CMAKE_INSTALL_FULL_LIBDIR@"
+includedir="@CMAKE_INSTALL_FULL_INCLUDEDIR@"
+
+Name: @PROJECT_NAME@
+Description: @CMAKE_PROJECT_DESCRIPTION@
+Version: @PROJECT_VERSION@
+Cflags: -I${includedir}
+Libs: -L${libdir} -lftxui-component -lftxui-dom -lftxui-screen