Instead of disabling gcc's deprecated declaration warnings about e.g.

std::auto_ptr in a whole bunch of individual Makefiles, make the warning
globally non-fatal instead.  This is similar to what was done to many
more non-fatal warnings from newer gcc versions.

lib/atf/libatf-c++/Makefile

@@ -48,9 +48,6 @@ CFLAGS+=	-I.
 
 CFLAGS+=	-DHAVE_CONFIG_H
 
-# Silence warnings about std::auto_ptr usage
-CWARNFLAGS+=	-Wno-deprecated-declarations
-
 SRCS=		application.cpp \
 		build.cpp \
 		check.cpp \

lib/libdevdctl/Makefile

@@ -18,8 +18,4 @@ WARNS?=	3
 PRIVATELIB=	true
 SHLIB_MAJOR=	0
 
-# Silence gcc warnings about deprecated std::auto_ptr, and various function
-# objects from <functional>.
-CWARNFLAGS+=	-Wno-deprecated-declarations
-
 .include <bsd.lib.mk>

libexec/atf/atf-check/Makefile

@@ -38,9 +38,6 @@ MAN=		atf-check.1
 CFLAGS+=	-I${ATF}
 CFLAGS+=	-DATF_SHELL='"/bin/sh"'
 
-# Silence warnings about std::auto_ptr usage
-CWARNFLAGS+=	-Wno-deprecated-declarations
-
 LIBADD=		atf_cxx
 
 HAS_TESTS=

libexec/atf/atf-sh/Makefile

@@ -65,9 +65,6 @@ CFLAGS+=	-DATF_PKGDATADIR='"${SHAREDIR}/atf"'
 CFLAGS+=	-DATF_SHELL='"/bin/sh"'
 CFLAGS+=	-I${ATF}
 
-# Silence warnings about std::auto_ptr usage
-CWARNFLAGS+=	-Wno-deprecated-declarations
-
 LIBADD=		atf_cxx
 
 FILESGROUPS=	SUBR

share/mk/atf.test.mk

@@ -55,8 +55,6 @@ LDADD.${_T}+= ${LIBATF_CXX} ${LIBATF_C}
 .endif
 TEST_INTERFACE.${_T}= atf
 .endfor
-# Silence warnings about std::auto_ptr usage
-CWARNFLAGS+= -Wno-deprecated-declarations
 .endif
 
 .if !empty(ATF_TESTS_SH)

share/mk/bsd.sys.mk

@@ -137,6 +137,7 @@ CWARNFLAGS+=	-Wno-error=address			\
 		-Wno-error=bool-compare			\
 		-Wno-error=cast-align			\
 		-Wno-error=clobbered			\
+		-Wno-error=deprecated-declarations	\
 		-Wno-error=enum-compare			\
 		-Wno-error=extra			\
 		-Wno-error=inline			\