add: support CMake.

CMakeLists.txt

@@ -0,0 +1,89 @@
+cmake_minimum_required(VERSION 3.23 FATAL_ERROR)
+
+project(MetroHash
+    VERSION 1.1.3
+    DESCRIPTION "MetroHash: Faster, Better Hash Functions"
+    HOMEPAGE_URL "http://www.jandrewrogers.com/2015/05/27/metrohash/"
+    LANGUAGES CXX
+)
+
+list(APPEND CMAKE_MESSAGE_CONTEXT top)
+
+if(CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR AND NOT CMAKE_BUILD_TYPE)
+    set(CMAKE_BUILD_TYPE Release CACHE STRING "Build type" FORCE)
+    set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS "Debug" "Release" "MinSizeRel" "RelWithDebInfo")
+endif()
+
+set(METRO_HASH_INSTALL_CMAKEDIR cmake CACHE PATH "Installation directory for config-file package cmake files")
+
+add_library(metrohash)
+target_sources(metrohash
+    PRIVATE
+        src/metrohash64.cpp
+        src/metrohash128.cpp
+        src/metrohash128crc.cpp
+        src/metrohash.h
+        src/metrohash64.h
+        src/metrohash128.h
+        src/metrohash128crc.h
+        src/platform.h
+        src/testvector.h
+)
+target_include_directories(metrohash
+    PRIVATE
+        $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/src>
+)
+target_compile_features(metrohash PUBLIC cxx_std_11)
+target_compile_options(metrohash
+    PRIVATE
+        $<$<CXX_COMPILER_ID:MSVC>:/W4 /WX> 
+        $<$<CXX_COMPILER_ID:GNU,Clang,AppleClang>:-Wall -Werror>
+)
+
+set_target_properties(metrohash
+    PROPERTIES
+		VERSION ${PROJECT_VERSION} # Contains 1.2.3
+		SOVERSION ${PROJECT_VERSION_MAJOR} # Contains only 1
+)
+set_target_properties(metrohash
+    PROPERTIES
+        DEBUG_POSTFIX d
+)
+
+include(GNUInstallDirs)
+
+install(TARGETS metrohash
+    EXPORT
+        metrohash_export
+    INCLUDES DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
+)
+
+install (
+    FILES
+        ${PROJECT_SOURCE_DIR}/src/metrohash.h
+        ${PROJECT_SOURCE_DIR}/src/metrohash64.h
+        ${PROJECT_SOURCE_DIR}/src/metrohash128.h
+        ${PROJECT_SOURCE_DIR}/src/metrohash128crc.h
+    DESTINATION
+        ${CMAKE_INSTALL_INCLUDEDIR}
+)
+
+install(EXPORT metrohash_export
+    FILE
+        metrohash-config.cmake
+    NAMESPACE
+        MetroHash::
+    DESTINATION
+        ${METRO_HASH_INSTALL_CMAKEDIR}
+)
+
+include(CMakePackageConfigHelpers)
+write_basic_package_version_file(
+    "metrohash-config-version.cmake"
+    COMPATIBILITY SameMajorVersion
+)
+
+install(FILES
+    "${CMAKE_CURRENT_BINARY_DIR}/metrohash-config-version.cmake"
+    DESTINATION "${METRO_HASH_INSTALL_CMAKEDIR}"
+)