Index: head/sysutils/acpica-tools/Makefile
===================================================================
--- head/sysutils/acpica-tools/Makefile	(revision 412124)
+++ head/sysutils/acpica-tools/Makefile	(revision 412125)
@@ -1,42 +1,40 @@
 # $FreeBSD$
 
 PORTNAME=	acpica
 PORTVERSION=	20160318
 CATEGORIES=	sysutils devel
 MASTER_SITES=	https://acpica.org/sites/acpica/files/ \
 		LOCAL/jkim
 PKGNAMESUFFIX=	-tools
 DISTNAME=	${PORTNAME}-unix2-${PORTVERSION}
 
 MAINTAINER=	jkim@FreeBSD.org
 COMMENT=	Tools from the ACPI Component Architecture (ACPICA) project
 
 LICENSE=	BSD3CLAUSE GPLv2
 LICENSE_COMB=	dual
 
 USES=		gmake
 
 BUILD_WRKSRC=	${WRKSRC}/generate/unix
 
 ACPICA_TOOLS=	acpibin acpidump acpiexec acpihelp acpinames acpisrc
 ACPICA_TOOLS+=	acpixtract iasl
 
 PLIST_FILES=	${ACPICA_TOOLS:S,^,bin/,}
 
 MAKE_ARGS=	HOST=_FreeBSD NOOPT=TRUE PROGS="${ACPICA_TOOLS}"
 MAKE_ARGS+=	CC="${CC}" LEX="${FLEX}" YACC="${YACC}"
 
 .include <bsd.port.pre.mk>
 
 .if ${OSVERSION} < 1001506
-BUILD_DEPENDS+=	bison:${PORTSDIR}/devel/bison
-BUILD_DEPENDS+=	gm4:${PORTSDIR}/devel/m4
-MAKE_ARGS+=	MACROPROC="${LOCALBASE}/bin/gm4"
-YACC=		${LOCALBASE}/bin/bison
+BUILD_DEPENDS+=	byacc>=20160324_1:devel/byacc
+YACC=		${LOCALBASE}/bin/yacc
 .endif
 
 do-install:
 	${INSTALL_PROGRAM} ${ACPICA_TOOLS:S,^,${BUILD_WRKSRC}/bin/,} \
 	    ${STAGEDIR}${PREFIX}/bin
 
 .include <bsd.port.post.mk>
Index: head/sysutils/acpica-tools/files/patch-generate_unix_iasl_Makefile
===================================================================
--- head/sysutils/acpica-tools/files/patch-generate_unix_iasl_Makefile	(revision 412124)
+++ head/sysutils/acpica-tools/files/patch-generate_unix_iasl_Makefile	(revision 412125)
@@ -1,20 +1,23 @@
 --- generate/unix/iasl/Makefile.orig	2016-03-18 16:25:41 UTC
 +++ generate/unix/iasl/Makefile
-@@ -274,12 +274,11 @@ include ../Makefile.rules
+@@ -274,12 +274,14 @@ include ../Makefile.rules
  # Function to safely execute yacc
  #
  safe_yacc = \
 -	_f=`echo $(1) | tr '[:upper:]' '[:lower:]'` &&\
 -	_d=`mktemp -d $(OBJDIR)/$$_f.XXXXXX` &&\
 -	_t=`basename $(3)` &&\
 -	$(YACC) $(YFLAGS) -p$(1) -o$$_d/$$_f.c -d $(2) &&\
 -	mv $$_d/$$_f.$${_t\#\#*.} $(3);\
 -	test -d $$_d && rm -fr $$_d
-+	_d=$$(mktemp -d '$(abspath $(OBJDIR))/$(1).XXXXXX') &&\
-+	cd "$$_d" &&\
-+	$(YACC) $(YFLAGS) -p$(1) -o$(1).c -d '$(abspath $(2))' &&\
-+	mv $(1)$(suffix $(3)) '$(abspath $(3))' &&\
-+	rm -fr "$$_d"
++	_d=`mktemp -d $(OBJDIR)/$(1).XXXXXX` &&\
++	cd $$_d &&\
++	$(YACC) $(YFLAGS) -d -p$(1) $(abspath $(2)) &&\
++	cd - &&\
++	mv $$_d/y.tab$(suffix $(3)) $(3);\
++	_r=$$?;\
++	rm -fr $$_d;\
++	exit $$_r
  
  #
  # Macro processing for iASL .y files