Update MaxmindDB to current git.

vendor/MaxmindDB/CMakeLists.txt

@@ -1,12 +1,18 @@
-cmake_minimum_required (VERSION 3.7)
+cmake_minimum_required (VERSION 3.9)
+
 project(maxminddb
   LANGUAGES C
-  VERSION 1.5.0
+  VERSION 1.6.0
 )
 set(MAXMINDDB_SOVERSION 0.0.7)
+set(CMAKE_C_STANDARD 99)
+set(CMAKE_C_EXTENSIONS OFF)
 
+if (WIN32)
+  option(MSVC_STATIC_RUNTIME "When ON the library will be built by using MT/MTd run-time libraries" OFF)
+endif()
 option(BUILD_SHARED_LIBS "Build shared libraries (.dll/.so) instead of static ones (.lib/.a)" OFF)
-option(BUILD_TESTING "Build test programs" OFF)
+option(BUILD_TESTING "Build test programs" ON)
 
 include(CheckTypeSize)
 check_type_size("unsigned __int128" UINT128)
@@ -30,7 +36,7 @@ if (${CMAKE_SYSTEM_NAME} MATCHES "Linux")
 endif()
 
 configure_file(${PROJECT_SOURCE_DIR}/include/maxminddb_config.h.cmake.in 
-               ${CMAKE_CURRENT_BINARY_DIR}/include/maxminddb_config.h)
+               ${PROJECT_SOURCE_DIR}/include/maxminddb_config.h)
 
 add_library(maxminddb
   src/maxminddb.c
@@ -52,13 +58,27 @@ endif()
 
 if(WIN32)
   target_link_libraries(maxminddb ws2_32)
+  if(BUILD_SHARED_LIBS)
+    set_target_properties(maxminddb PROPERTIES WINDOWS_EXPORT_ALL_SYMBOLS ON)
+  endif()
+  if(MSVC_STATIC_RUNTIME)
+    # On MSVC, when MSVC_STATIC_RUNTIME is ON, MT (Release) and MTd (Debug)
+    # run-time libraries will be used instead of MD/MDd. The default is OFF so
+    # MD/MDd are used when nothing related is passed.
+    #
+    # Adapted from https://gitlab.kitware.com/cmake/community/-/wikis/FAQ#make-override-files
+    set(CMAKE_USER_MAKE_RULES_OVERRIDE
+        ${CMAKE_CURRENT_SOURCE_DIR}/c_flag_overrides.cmake)
+    set(CMAKE_USER_MAKE_RULES_OVERRIDE_CXX
+        ${CMAKE_CURRENT_SOURCE_DIR}/cxx_flag_overrides.cmake)
+  endif()
 endif()
 
-set(CMAKE_SHARED_LIBRARY_PREFIX lib)
-set(CMAKE_STATIC_LIBRARY_PREFIX lib)
-
-target_include_directories(maxminddb PUBLIC ${CMAKE_CURRENT_BINARY_DIR}/include)
-target_include_directories(maxminddb PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include)
+target_include_directories(maxminddb PUBLIC
+  $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}>
+  $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
+  $<INSTALL_INTERFACE:include>
+)
 
 set(MAXMINDB_HEADERS
   include/maxminddb.h
@@ -66,17 +86,14 @@ set(MAXMINDB_HEADERS
 )
 set_target_properties(maxminddb PROPERTIES PUBLIC_HEADER "${MAXMINDB_HEADERS}")
 
-#install(TARGETS maxminddb
-#        EXPORT maxminddb
-#        ARCHIVE DESTINATION lib
-#        PUBLIC_HEADER DESTINATION include/
-#)
+install(TARGETS maxminddb
+	EXPORT maxminddb)
 
 # This is required to work with FetchContent
-#install(EXPORT maxminddb
-#        FILE maxminddb-config.cmake
-#        NAMESPACE maxminddb::
-#        DESTINATION lib/cmake/maxminddb)
+install(EXPORT maxminddb
+        FILE maxminddb-config.cmake
+        NAMESPACE maxminddb::
+        DESTINATION lib/cmake/maxminddb)
 
 # We always want to build mmdblookup
 add_subdirectory(bin)