https://github.com/rsyslog/rsyslog/issues/2612

--- a/configure.ac
+++ b/configure.ac
@@ -254,7 +254,7 @@ AC_LINK_IFELSE([AC_LANG_PROGRAM(, return __builtin_expect(main != 0, 1))],
 # speeds up processig.
 # note that when automic operations are enabled but not available, they
 # will silently NOT be used!
-AC_ARG_ENABLE(regexp,
+AC_ARG_ENABLE(atomic_operations,
         [AS_HELP_STRING([--enable-atomic-operations],[Enable atomic operation support @<:@default=yes@:>@])],
         [case "${enableval}" in
          yes) enable_atomic_operations="yes" ;;