cmake: pick a better IPv6 feature flag when assembling the feature list

Before this patch it used `ENABLE_IPV6`, the configuration intent.
Replace with `USE_IPV6` which is the actual setting passed to C.

The two can be different for targets without IPv6 support.

Closes #15980

diff --git a/CMakeLists.txt b/CMakeLists.txt
index b6ac4231ca34138d2033dce670133c7ac8609ae9..527e6c815735f45ed13a05b487932f4d177414e9 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2056,7 +2056,7 @@ message(STATUS "Protocols: ${_support_protocols_lower}")
 # Clear list and try to detect available features
 set(_items "")
 curl_add_if("SSL"           _ssl_enabled)
-curl_add_if("IPv6"          ENABLE_IPV6)
+curl_add_if("IPv6"          USE_IPV6)
 curl_add_if("UnixSockets"   USE_UNIX_SOCKETS)
 curl_add_if("libz"          HAVE_LIBZ)
 curl_add_if("brotli"        HAVE_BROTLI)