Make --disable-guards the default for the time being.

configure.ac

@@ -209,15 +209,15 @@ dnl User setting: disable guards (race protection)
 dnl
 
 AC_ARG_ENABLE([guards],
-    [AS_HELP_STRING([--disable-guards],
-        [disable race protection in HPC-GAP])],
+    [AS_HELP_STRING([--enable-guards],
+        [enable guards for race protection in HPC-GAP])],
     [enable_guards=$enableval],
-    [enable_guards=yes])
+    [enable_guards=no])
 
 AS_IF([[test "x$enable_guards" == "xyes"]], [
     AC_DEFINE([USE_HPC_GUARDS], [1], [define as 1 if guards should be checked])
 ])
-AC_MSG_CHECKING([whether to use race protection in HPC-GAP])
+AC_MSG_CHECKING([whether to use guards for race protection in HPC-GAP])
 AC_MSG_RESULT([$enable_guards])
 
 dnl
@@ -907,6 +907,9 @@ AS_IF([test "x$enable_hpcgap" = xyes],[
   AS_BOX([WARNING: Experimental HPC-GAP mode enabled])
   dnl also enable backtrace, to help debug spurious crashes
   AC_DEFINE([GAP_PRINT_BACKTRACE], [1], [to enable backtraces upon crashes])
+  AS_IF([test "x$enable_guards" = xno], [
+    AS_BOX([WARNING: HPC-GAP guards (race condition protection) are disabled.])
+    ])
   ])
 
 AS_IF([test "x$enable_macos_tls_asm" = xno],[

etc/ci-prepare.sh

@@ -23,7 +23,7 @@ BUILDDIR=$PWD
 
 if [[ $HPCGAP = yes ]]
 then
-  CONFIGFLAGS="--enable-hpcgap $CONFIGFLAGS"
+  CONFIGFLAGS="--enable-hpcgap --enable-guards $CONFIGFLAGS"
 fi