Nix,CMake: Add installation

CMakeLists.txt

@@ -10,7 +10,11 @@ set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 add_library(muopt INTERFACE)
 add_library(muopt::muopt ALIAS muopt)
-target_include_directories(muopt INTERFACE ${CMAKE_CURRENT_SOURCE_DIR}/include)
+target_include_directories(
+    muopt INTERFACE
+    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
+    $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
+)
 target_compile_features(muopt INTERFACE cxx_std_17)
 
 # ------------------------------------------------------------------------------
@@ -50,3 +54,40 @@ endif()
 if(MUOPT_BUILD_FUZZ)
     add_subdirectory(fuzz)
 endif()
+
+# ------------------------------------------------------------------------------
+# Install & Package Export
+# ------------------------------------------------------------------------------
+
+include(GNUInstallDirs)
+include(CMakePackageConfigHelpers)
+
+configure_package_config_file(
+    ${CMAKE_CURRENT_SOURCE_DIR}/cmake/muoptConfig.cmake.in
+    ${CMAKE_CURRENT_BINARY_DIR}/muoptConfig.cmake
+    INSTALL_DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/muopt
+)
+
+write_basic_package_version_file(
+    ${CMAKE_CURRENT_BINARY_DIR}/muoptConfigVersion.cmake
+    VERSION ${PROJECT_VERSION}
+    COMPATIBILITY SameMajorVersion
+)
+
+install(DIRECTORY include/muopt DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
+
+install(TARGETS muopt EXPORT muoptTargets)
+
+install(
+    EXPORT muoptTargets
+    FILE muoptTargets.cmake
+    NAMESPACE muopt::
+    DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/muopt
+)
+
+install(
+    FILES
+        ${CMAKE_CURRENT_BINARY_DIR}/muoptConfig.cmake
+        ${CMAKE_CURRENT_BINARY_DIR}/muoptConfigVersion.cmake
+    DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/muopt
+)

cmake/muoptConfig.cmake.in

@@ -0,0 +1,4 @@
+@PACKAGE_INIT@
+
+include("${CMAKE_CURRENT_LIST_DIR}/muoptTargets.cmake")
+check_required_components(muopt)

flake.nix

@@ -0,0 +1,67 @@
+{
+  description = "muopt";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+    flake-parts.url = "github:hercules-ci/flake-parts";
+  };
+
+  outputs =
+    inputs:
+    inputs.flake-parts.lib.mkFlake { inherit inputs; } {
+      imports = [
+        inputs.flake-parts.flakeModules.easyOverlay
+      ];
+
+      systems = [
+        "x86_64-linux"
+        "aarch64-linux"
+        "x86_64-darwin"
+        "aarch64-darwin"
+      ];
+
+      perSystem =
+        { pkgs, ... }:
+        let
+          version = "0.1.0";
+
+          muopt = pkgs.stdenv.mkDerivation {
+            pname = "muopt";
+            inherit version;
+            src = ./.;
+
+            nativeBuildInputs = [ pkgs.cmake ];
+            cmakeFlags = [
+              "-DMUOPT_BUILD_EXAMPLES=OFF"
+              "-DMUOPT_BUILD_TESTS=OFF"
+              "-DMUOPT_BUILD_FUZZ=OFF"
+            ];
+
+            meta = {
+              description = "A header-only C++17 micro-library for argument parsing";
+              homepage = "https://github.com/secona/muopt";
+              license = pkgs.lib.licenses.mit;
+              platforms = pkgs.lib.platforms.all;
+            };
+          };
+        in
+        {
+          overlayAttrs = { inherit muopt; };
+
+          packages.default = muopt;
+
+          devShells.default =
+            pkgs.mkShell.override
+              {
+                stdenv = pkgs.clangStdenv;
+              }
+              {
+                packages = with pkgs; [
+                  clang-tools
+                  cmake
+                  ninja
+                ];
+              };
+        };
+    };
+}