Debian/Hurd doesn't support auth_socket

Hurd doesn't have the mechanism to identify the user connecting to
a socket via a system call as MDEV-8535 highlighted. As such it
can't be supported so we disable it in Debian's mysql_release profile.

Hurd string from uname -m, "SYSTEM processor: i686-AT386" in mariadb
output. And wiki reference https://en.wikipedia.org/wiki/Uname

Origin: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1006531

Author: grooverdan

cmake/build_configurations/mysql_release.cmake

@@ -121,7 +121,10 @@ ELSEIF(DEB)
   SET(WITH_ZLIB system CACHE STRING "")
   SET(WITH_LIBWRAP ON)
   SET(HAVE_EMBEDDED_PRIVILEGE_CONTROL ON)
-  SET(PLUGIN_AUTH_SOCKET YES CACHE STRING "")
+  # No hurd implementation
+  IF(NOT CMAKE_SYSTEM_PROCESSOR STREQUAL "i686-AT386")
+    SET(PLUGIN_AUTH_SOCKET YES CACHE STRING "")
+  ENDIF()
   SET(WITH_EMBEDDED_SERVER ON CACHE BOOL "")
   SET(WITH_PCRE system CACHE STRING "")
   SET(CLIENT_PLUGIN_ZSTD OFF)