Switch to ELF toolchain readelf(1)

ELF toolchain readelf lacked some functionality at the time other tools
(like size, strip, nm, etc.) were switched over to the ELF toolchain
versions. That has been addressed as of the last update, so we can add
it to the list.

PR:		198950 [exp-run]
Reviewed by:	bapt, imp, rpaulo
Relnotes:	yes
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D2156

gnu/usr.bin/binutils/Makefile

@@ -13,7 +13,7 @@ SUBDIR=	doc\
 	${_nm} \
 	objcopy \
 	objdump \
-	readelf \
+	${_readelf} \
 	${_size} \
 	${_strings} \
 	${_strip}
@@ -21,6 +21,7 @@ SUBDIR=	doc\
 .if ${MK_ELFTOOLCHAIN_TOOLS} == "no"
 _addr2line=	addr2line
 _nm=		nm
+_readelf=	readelf
 _size=		size
 _strings=	strings
 _strip=		strip

usr.bin/Makefile

@@ -133,6 +133,7 @@ SUBDIR=	${_addr2line} \
 	procstat \
 	protect \
 	rctl \
+	${_readelf} \
 	renice \
 	rev \
 	revoke \
@@ -238,6 +239,7 @@ SUBDIR+=	ee
 _addr2line=	addr2line
 _elfcopy=	elfcopy
 _nm=		nm
+_readelf=	readelf
 _size=		size
 _strings=	strings
 .endif