devel/elfutils: Unbreak gcc8 build

Drop one new gcc8 warning, and fix another in the FreeBSD glibc-
compatibility shim patch.

Re-enable gcc8 option (USE_GCC= yes).

Bump PORTREVISION due to the patch change (no functional change).

PR:		232932
Reported by:	gerald, kib
Reviewed by:	bdrewery
Approved by:	bdrewery
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D17882

devel/elfutils/Makefile

@@ -3,6 +3,7 @@
 
 PORTNAME=	elfutils
 PORTVERSION=	0.174
+PORTREVISION=	1
 CATEGORIES=	devel
 MASTER_SITES=	https://sourceware.org/elfutils/ftp/${PORTVERSION}/
 
@@ -33,11 +34,13 @@ NLS_USES_OFF=	gettext  # used anyway
 NLS_CONFIGURE_ENABLE=	nls
 
 USES=		autoreconf gmake libtool tar:bzip2
-USE_GCC=	7
+USE_GCC=	yes
 GNU_CONFIGURE=	yes
 USE_LDCONFIG=	yes
 
 CFLAGS+=	-Wno-null-dereference -Wno-unused-value
+# For GCC8:
+CFLAGS+=	-Wno-cast-function-type
 # Give i386 a prayer of building, and we can fix the warnings later:
 CFLAGS_i386+=	-Wno-error
 

devel/elfutils/files/patch-lib_eu-config.h

@@ -1,12 +1,13 @@
 --- lib/eu-config.h.orig	2015-06-11 11:38:55 UTC
 +++ lib/eu-config.h
-@@ -187,4 +187,170 @@ asm (".section predict_data, \"aw\"; .pr
+@@ -187,4 +187,171 @@ asm (".section predict_data, \"aw\"; .pr
  #endif
  
  
 +/* FreeBSD ports of glibcisms */
 +#include <sys/cdefs.h>
 +#include <libgen.h>
++#include <limits.h>
 +#include <stdarg.h>
 +#include <stdint.h>
 +#include <stdlib.h>
@@ -40,7 +41,7 @@
 +rawmemchr(const void *s, int c)
 +{
 +
-+	return (memchr(s, c, SIZE_MAX));
++	return (memchr(s, c, SSIZE_MAX));
 +}
 +
 +static inline void