cmake: set HAVE_GETADDRINFO_THREADSAFE on Windows

autotools enables this configuration option unconditionally for Windows
[^1]. Do the same in CMake.

The above will make this work for all reasonably recent environments.
The logic present in `lib/config-win32.h` [^2] has the following
exceptions which we did not cover in this CMake update:

- Builds targeting Windows 2000 and earlier
- MS Visual C++ 5.0 (1997) and earlier

Also make sure to disable this feature when `HAVE_GETADDRINFO` isn't
set, to avoid a broken build. We might want to handle that in the C
sources in a future commit.

[^1]: 68fa9bf3f5/m4/curl-functions.m4 (L2067-L2070)

[^2]: 68fa9bf3f5/lib/config-win32.h (L511-L528)

Closes #9727

CMake/Platforms/WindowsCache.cmake

@@ -70,6 +70,7 @@ if(NOT UNIX)
     set(HAVE_UTIME 1)
     set(HAVE_RAND_EGD 0)
     set(HAVE_GMTIME_R 0)
+    set(HAVE_GETADDRINFO_THREADSAFE 1)
     set(HAVE_GETHOSTBYNAME_R 0)
     set(HAVE_SIGNAL 1)
 

CMakeLists.txt

@@ -1045,6 +1045,9 @@ check_symbol_exists(_strtoi64      "${CURL_INCLUDES}" HAVE__STRTOI64)
 check_symbol_exists(strerror_r     "${CURL_INCLUDES}" HAVE_STRERROR_R)
 check_symbol_exists(siginterrupt   "${CURL_INCLUDES}" HAVE_SIGINTERRUPT)
 check_symbol_exists(getaddrinfo    "${CURL_INCLUDES}" HAVE_GETADDRINFO)
+if(NOT HAVE_GETADDRINFO)
+  set(HAVE_GETADDRINFO_THREADSAFE OFF)
+endif()
 check_symbol_exists(freeaddrinfo   "${CURL_INCLUDES}" HAVE_FREEADDRINFO)
 check_symbol_exists(pipe           "${CURL_INCLUDES}" HAVE_PIPE)
 check_symbol_exists(ftruncate      "${CURL_INCLUDES}" HAVE_FTRUNCATE)

lib/curl_config.h.cmake

@@ -195,6 +195,9 @@
 /* Define to 1 if you have a working getaddrinfo function. */
 #cmakedefine HAVE_GETADDRINFO 1
 
+/* Define to 1 if the getaddrinfo function is threadsafe. */
+#cmakedefine HAVE_GETADDRINFO_THREADSAFE 1
+
 /* Define to 1 if you have the `geteuid' function. */
 #cmakedefine HAVE_GETEUID 1