Remove the configure option for disabling the reference cycle GC.

configure

 #! /bin/sh
-# From configure.in Revision: 1.325 .
+# From configure.in Revision: 1.327 .
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.53.
 #
@@ -843,7 +843,6 @@ Optional Packages:
   --with(out)-threads=DIRECTORY disable/enable thread support
   --with(out)-thread=DIRECTORY  deprecated; use --with(out)-threads
   --with-pth                      use GNU pth threading libraries
-  --with(out)-cycle-gc            disable/enable garbage collection
   --with(out)-universal-newlines            disable/enable foreign newlines
   --with(out)-doc-strings         disable/enable documentation strings
   --with(out)-pymalloc            disable/enable specialized mallocs
@@ -11055,30 +11054,6 @@ if test "$ipv6" = "yes" -a "$ipv6lib" != "none"; then
 	fi
 fi
 
-# Check for GC support
-echo "$as_me:$LINENO: checking for --with-cycle-gc" >&5
-echo $ECHO_N "checking for --with-cycle-gc... $ECHO_C" >&6
-
-# Check whether --with-cycle-gc or --without-cycle-gc was given.
-if test "${with_cycle_gc+set}" = set; then
-  withval="$with_cycle_gc"
-
-fi;
-
-if test -z "$with_cycle_gc"
-then with_cycle_gc="yes"
-fi
-if test "$with_cycle_gc" != "no"
-then
-
-cat >>confdefs.h <<\_ACEOF
-#define WITH_CYCLE_GC 1
-_ACEOF
-
-fi
-echo "$as_me:$LINENO: result: $with_cycle_gc" >&5
-echo "${ECHO_T}$with_cycle_gc" >&6
-
 # Check for universal newline support
 echo "$as_me:$LINENO: checking for --with-universal-newline" >&5
 echo $ECHO_N "checking for --with-universal-newline... $ECHO_C" >&6
@@ -11441,7 +11416,6 @@ echo "${ECHO_T}MACHDEP_OBJS" >&6
 
 
 
-
 
 
 for ac_func in alarm chown chroot clock confstr ctermid ctermid_r execv \

configure.in

@@ -1453,21 +1453,6 @@ if test "$ipv6" = "yes" -a "$ipv6lib" != "none"; then
 	fi
 fi
 
-# Check for GC support
-AC_MSG_CHECKING(for --with-cycle-gc)
-AC_ARG_WITH(cycle-gc,
-[  --with(out)-cycle-gc            disable/enable garbage collection])
-
-if test -z "$with_cycle_gc"
-then with_cycle_gc="yes"
-fi
-if test "$with_cycle_gc" != "no"
-then
-    AC_DEFINE(WITH_CYCLE_GC, 1, 
-     [Define if you want to compile in cycle garbage collection.])
-fi
-AC_MSG_RESULT($with_cycle_gc)
-
 # Check for universal newline support
 AC_MSG_CHECKING(for --with-universal-newline)
 AC_ARG_WITH(universal-newlines,