Fix build with gperf 3.1.
https://github.com/jordansissel/grok/issues/28
https://github.com/jordansissel/grok/issues/29
--- Makefile.orig	2011-10-28 02:17:11.000000000 -0500
+++ Makefile	2022-01-14 01:26:51.000000000 -0600
@@ -209,10 +209,6 @@
 	rpcgen -h $< -o $@
 
 %.c: %.gperf
-	@if $(GPERF) --version | head -1 | egrep -v '3\.[0-9]+\.[0-9]+' ; then \
-		echo "We require gperf version >= 3.0.3" ; \
-		exit 1; \
-	fi
 	$(GPERF) $< > $@
 
 conf.tab.c conf.tab.h: conf.y
--- grok_matchconf_macro.h.orig	2011-10-28 02:17:11.000000000 -0500
+++ grok_matchconf_macro.h	2022-01-14 01:50:28.000000000 -0600
@@ -19,6 +19,6 @@
 #endif
 
 /* this function is generated by gperf */
-const struct strmacro *patname2macro(const char *str, unsigned int len);
+const struct strmacro *patname2macro(const char *str, size_t len);
 
 #endif /* _GROK_MATCHCONF_MACRO_ */