ext/zlib.patch

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 15ceebe..03825a2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,23 +1,21 @@
-cmake_minimum_required(VERSION 2.4.4...3.15.0)
-set(CMAKE_ALLOW_LOOSE_LOOP_CONSTRUCTS ON)
+cmake_minimum_required(VERSION 3.15)
 
-project(zlib C)
-
-set(VERSION "1.3.1")
+project(zlib VERSION 1.3.1 LANGUAGES C)
 
 option(ZLIB_BUILD_EXAMPLES "Enable Zlib Examples" ON)
 
-set(INSTALL_BIN_DIR "${CMAKE_INSTALL_PREFIX}/bin" CACHE PATH "Installation directory for executables")
-set(INSTALL_LIB_DIR "${CMAKE_INSTALL_PREFIX}/lib" CACHE PATH "Installation directory for libraries")
-set(INSTALL_INC_DIR "${CMAKE_INSTALL_PREFIX}/include" CACHE PATH "Installation directory for headers")
-set(INSTALL_MAN_DIR "${CMAKE_INSTALL_PREFIX}/share/man" CACHE PATH "Installation directory for manual pages")
-set(INSTALL_PKGCONFIG_DIR "${CMAKE_INSTALL_PREFIX}/share/pkgconfig" CACHE PATH "Installation directory for pkgconfig (.pc) files")
+include(GNUInstallDirs)
+set(INSTALL_BIN_DIR "${CMAKE_INSTALL_BINDIR}" CACHE PATH "Installation directory for executables")
+set(INSTALL_LIB_DIR "${CMAKE_INSTALL_LIBDIR}" CACHE PATH "Installation directory for libraries")
+set(INSTALL_INC_DIR "${CMAKE_INSTALL_INCLUDEDIR}" CACHE PATH "Installation directory for headers")
+set(INSTALL_MAN_DIR "${CMAKE_INSTALL_MANDIR}" CACHE PATH "Installation directory for manual pages")
+set(INSTALL_PKGCONFIG_DIR "${CMAKE_INSTALL_DATADIR}/pkgconfig" CACHE PATH "Installation directory for pkgconfig (.pc) files")
 
 include(CheckTypeSize)
 include(CheckFunctionExists)
 include(CheckIncludeFile)
 include(CheckCSourceCompiles)
-enable_testing()
+include(CTest)
 
 check_include_file(sys/types.h HAVE_SYS_TYPES_H)
 check_include_file(stdint.h    HAVE_STDINT_H)
@@ -149,12 +147,21 @@ if(MINGW)
     set(ZLIB_DLL_SRCS ${CMAKE_CURRENT_BINARY_DIR}/zlib1rc.obj)
 endif(MINGW)
 
-add_library(zlib SHARED ${ZLIB_SRCS} ${ZLIB_DLL_SRCS} ${ZLIB_PUBLIC_HDRS} ${ZLIB_PRIVATE_HDRS})
-target_include_directories(zlib PUBLIC ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR})
-add_library(zlibstatic STATIC ${ZLIB_SRCS} ${ZLIB_PUBLIC_HDRS} ${ZLIB_PRIVATE_HDRS})
-target_include_directories(zlibstatic PUBLIC ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR})
-set_target_properties(zlib PROPERTIES DEFINE_SYMBOL ZLIB_DLL)
-set_target_properties(zlib PROPERTIES SOVERSION 1)
+if(BUILD_SHARED_LIBS)
+  add_library(ZLIB SHARED ${ZLIB_SRCS} ${ZLIB_DLL_SRCS} ${ZLIB_PUBLIC_HDRS} ${ZLIB_PRIVATE_HDRS})
+  set_target_properties(ZLIB PROPERTIES DEFINE_SYMBOL ZLIB_DLL)
+  set_target_properties(ZLIB PROPERTIES SOVERSION 1)
+else()
+  add_library(ZLIB STATIC ${ZLIB_SRCS} ${ZLIB_PUBLIC_HDRS} ${ZLIB_PRIVATE_HDRS})
+endif()
+
+target_include_directories(ZLIB PUBLIC
+  $<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}>
+  $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
+  $<INSTALL_INTERFACE:include>)
+
+add_library(ZLIB::ZLIB ALIAS ZLIB)
+
 
 if(NOT CYGWIN)
     # This property causes shared libraries on Linux to have the full version
@@ -164,26 +171,49 @@ if(NOT CYGWIN)
     #
     # This has no effect with MSVC, on that platform the version info for
     # the DLL comes from the resource file win32/zlib1.rc
-    set_target_properties(zlib PROPERTIES VERSION ${ZLIB_FULL_VERSION})
+    set_target_properties(ZLIB PROPERTIES VERSION ${ZLIB_FULL_VERSION})
 endif()
 
 if(UNIX)
     # On unix-like platforms the library is almost always called libz
-   set_target_properties(zlib zlibstatic PROPERTIES OUTPUT_NAME z)
-   if(NOT APPLE AND NOT(CMAKE_SYSTEM_NAME STREQUAL AIX))
-     set_target_properties(zlib PROPERTIES LINK_FLAGS "-Wl,--version-script,\"${CMAKE_CURRENT_SOURCE_DIR}/zlib.map\"")
+   set_target_properties(ZLIB PROPERTIES OUTPUT_NAME z)
+   if(NOT APPLE AND NOT(CMAKE_SYSTEM_NAME STREQUAL AIX) AND BUILD_SHARED_LIBS)
+     set_target_properties(ZLIB PROPERTIES LINK_FLAGS "-Wl,--version-script,\"${CMAKE_CURRENT_SOURCE_DIR}/zlib.map\"")
    endif()
 elseif(BUILD_SHARED_LIBS AND WIN32)
     # Creates zlib1.dll when building shared library version
-    set_target_properties(zlib PROPERTIES SUFFIX "1.dll")
+    set_target_properties(ZLIB PROPERTIES SUFFIX "1.dll")
+endif()
+
+if(NOT UNIX)
+  if(BUILD_SHARED_LIBS)
+    set_target_properties(ZLIB PROPERTIES OUTPUT_NAME zlib)
+  else()
+    set_target_properties(ZLIB PROPERTIES OUTPUT_NAME zlibstatic)
+  endif()
 endif()
 
-if(NOT SKIP_INSTALL_LIBRARIES AND NOT SKIP_INSTALL_ALL )
-    install(TARGETS zlib zlibstatic
-        RUNTIME DESTINATION "${INSTALL_BIN_DIR}"
-        ARCHIVE DESTINATION "${INSTALL_LIB_DIR}"
-        LIBRARY DESTINATION "${INSTALL_LIB_DIR}" )
+if(NOT SKIP_INSTALL_LIBRARIES AND NOT SKIP_INSTALL_ALL)
+  install(TARGETS ZLIB
+    EXPORT ZLIBTargets
+    RUNTIME DESTINATION "${INSTALL_BIN_DIR}"
+    ARCHIVE DESTINATION "${INSTALL_LIB_DIR}"
+    LIBRARY DESTINATION "${INSTALL_LIB_DIR}")
+  install(EXPORT ZLIBTargets
+    NAMESPACE ZLIB::
+    DESTINATION lib/cmake/ZLIB)
+  include(CMakePackageConfigHelpers)
+  write_basic_package_version_file("${CMAKE_CURRENT_BINARY_DIR}/ZLIBConfigVersion.cmake"
+    VERSION ${PROJECT_VERSION}
+    COMPATIBILITY SameMajorVersion)
+  file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/ZLIBConfig.cmake"
+    "include(\"\${CMAKE_CURRENT_LIST_DIR}/ZLIBTargets.cmake\")"
+  )
+  install(FILES "${CMAKE_CURRENT_BINARY_DIR}/ZLIBConfig.cmake"
+    "${CMAKE_CURRENT_BINARY_DIR}/ZLIBConfigVersion.cmake"
+    DESTINATION lib/cmake/ZLIB)
 endif()
+
 if(NOT SKIP_INSTALL_HEADERS AND NOT SKIP_INSTALL_ALL )
     install(FILES ${ZLIB_PUBLIC_HDRS} DESTINATION "${INSTALL_INC_DIR}")
 endif()
@@ -199,20 +229,20 @@ endif()
 #============================================================================
 if(ZLIB_BUILD_EXAMPLES)
     add_executable(example test/example.c)
-    target_link_libraries(example zlib)
+    target_link_libraries(example ZLIB)
     add_test(example example)
 
     add_executable(minigzip test/minigzip.c)
-    target_link_libraries(minigzip zlib)
+    target_link_libraries(minigzip ZLIB)
 
     if(HAVE_OFF64_T)
         add_executable(example64 test/example.c)
-        target_link_libraries(example64 zlib)
+        target_link_libraries(example64 ZLIB)
         set_target_properties(example64 PROPERTIES COMPILE_FLAGS "-D_FILE_OFFSET_BITS=64")
         add_test(example64 example64)
 
         add_executable(minigzip64 test/minigzip.c)
-        target_link_libraries(minigzip64 zlib)
+        target_link_libraries(minigzip64 ZLIB)
         set_target_properties(minigzip64 PROPERTIES COMPILE_FLAGS "-D_FILE_OFFSET_BITS=64")
     endif()
 endif()