Fix build with recent binutils

Recent binutils considered the .gnu.warning.symbol section as a fatal error when
run with --fatal-warnings which makes any users of "insecure" functions from
libc failing to build with recent binutils.

Introduce a new macro: LD_FATAL_WARNINGS=no to run ld(1) with
--no-fatal-warnings for the users of "insecure" functions

Differential Revision:	https://reviews.freebsd.org/D1320

gnu/lib/libssp/Makefile

@@ -15,6 +15,7 @@ SRCDIR=	${GCCLIB}/libssp
 
 LIB=		ssp
 SHLIB_MAJOR=	0
+LD_FATAL_WARNINGS=	no
 
 SRCS=	ssp.c gets-chk.c memcpy-chk.c memmove-chk.c mempcpy-chk.c \
 	memset-chk.c snprintf-chk.c sprintf-chk.c stpcpy-chk.c \

lib/libbsnmp/libbsnmp/Makefile

@@ -9,6 +9,7 @@ CONTRIB= ${.CURDIR}/../../../contrib/bsnmp/lib
 
 LIB=	bsnmp
 SHLIB_MAJOR=	6
+LD_FATAL_WARNINGS=	no
 
 CFLAGS+= -I${CONTRIB} -DHAVE_ERR_H -DHAVE_GETADDRINFO -DHAVE_STRLCPY
 CFLAGS+= -DHAVE_STDINT_H -DHAVE_INTTYPES_H -DQUADFMT='"llu"' -DQUADXFMT='"llx"'

share/mk/bsd.lib.mk

@@ -207,7 +207,12 @@ _LIBS+=		${SHLIB_NAME}
 
 SOLINKOPTS=	-shared -Wl,-x
 .if !defined(ALLOW_SHARED_TEXTREL)
-SOLINKOPTS+=	-Wl,--fatal-warnings -Wl,--warn-shared-textrel
+.if defined(LD_FATAL_WARNINGS) && ${LD_FATAL_WARNINGS} == "no"
+SOLINKOPTS+=	-Wl,--no-fatal-warnings
+.else
+SOLINKOPTS+=	-Wl,--fatal-warnings
+.endif
+SOLINKOPTS+=	-Wl,--warn-shared-textrel
 .endif
 
 .if target(beforelinking)