diff --git a/src/config.h.generic b/src/config.h.generic
index 4ab845c..d2ed352 100644
--- a/src/config.h.generic
+++ b/src/config.h.generic
@@ -303,6 +303,11 @@ sure both macros are undefined; an emulation function will then be used. */
 /* Define to any value to enable callout script support in pcre2grep. */
 /* #undef SUPPORT_PCRE2GREP_CALLOUT */
 
+/* Define to any value to enable fork support in pcre2grep callout scripts.
+   This will have no effect unless SUPPORT_PCRE2GREP_CALLOUT is also defined.
+   */
+/* #undef SUPPORT_PCRE2GREP_CALLOUT_FORK */
+
 /* Define to any value to enable JIT support in pcre2grep. Note that this will
    have no effect unless SUPPORT_JIT is also defined. */
 /* #undef SUPPORT_PCRE2GREP_JIT */