Index: lib/clang/llvm.build.mk
===================================================================
--- lib/clang/llvm.build.mk
+++ lib/clang/llvm.build.mk
@@ -95,7 +95,7 @@
 CFLAGS+=	-fdata-sections
 LDFLAGS+=	-Wl,--gc-sections
 
-CXXFLAGS+=	-std=c++11
+CXXSTD?=	c++11
 CXXFLAGS+=	-fno-exceptions
 CXXFLAGS+=	-fno-rtti
 CXXFLAGS.clang+= -stdlib=libc++
Index: lib/libc++/Makefile
===================================================================
--- lib/libc++/Makefile
+++ lib/libc++/Makefile
@@ -76,9 +76,7 @@
 CFLAGS+=	-nostdlib
 CFLAGS+=	-D_LIBCPP_BUILDING_LIBRARY
 CFLAGS+=	-DLIBCXXRT
-.if empty(CXXFLAGS:M-std=*)
-CXXFLAGS+=	-std=c++11
-.endif
+CXXSTD=		c++11
 
 LIBADD+=	cxxrt
 INCSGROUPS=	STD EXP EXT
Index: lib/libc++experimental/Makefile
===================================================================
--- lib/libc++experimental/Makefile
+++ lib/libc++experimental/Makefile
@@ -20,8 +20,6 @@
 CXXFLAGS+=	-nostdlib
 CXXFLAGS+=	-D_LIBCPP_BUILDING_LIBRARY
 CXXFLAGS+=	-DLIBCXXRT
-.if empty(CXXFLAGS:M-std=*)
-CXXFLAGS+=	-std=c++14
-.endif
+CXXSTD=		c++14
 
 .include <bsd.lib.mk>
Index: lib/libc++fs/Makefile
===================================================================
--- lib/libc++fs/Makefile
+++ lib/libc++fs/Makefile
@@ -22,8 +22,6 @@
 CXXFLAGS+=	-nostdlib
 CXXFLAGS+=	-D_LIBCPP_BUILDING_LIBRARY
 CXXFLAGS+=	-DLIBCXXRT
-.if empty(CXXFLAGS:M-std=*)
-CXXFLAGS+=	-std=c++14
-.endif
+CXXSTD=		c++14
 
 .include <bsd.lib.mk>
Index: lib/libclang_rt/Makefile.inc
===================================================================
--- lib/libclang_rt/Makefile.inc
+++ lib/libclang_rt/Makefile.inc
@@ -41,4 +41,4 @@
 CXXFLAGS+=	-fvisibility-inlines-hidden
 CXXFLAGS+=	-fvisibility=hidden
 CFLAGS+=	-I${CRTSRC}/lib
-CXXFLAGS+=	-std=c++11
+CXXSTD=		c++11
Index: lib/libcxxrt/Makefile
===================================================================
--- lib/libcxxrt/Makefile
+++ lib/libcxxrt/Makefile
@@ -22,9 +22,7 @@
 
 WARNS=		0
 CFLAGS+=	-isystem ${SRCDIR} -nostdinc++
-.if empty(CXXFLAGS:M-std=*)
-CXXFLAGS+=	-std=c++11
-.endif
+CXXSTD=		c++11
 VERSION_MAP=	${.CURDIR}/Version.map
 
 .include <bsd.lib.mk>
Index: lib/libgcc_eh/Makefile.inc
===================================================================
--- lib/libgcc_eh/Makefile.inc
+++ lib/libgcc_eh/Makefile.inc
@@ -27,10 +27,8 @@
 .endfor
 
 CFLAGS+=	-I${UNWINDINCDIR} -I${.CURDIR} -D_LIBUNWIND_IS_NATIVE_ONLY
-.if empty(CXXFLAGS:M-std=*)
-CXXFLAGS+=	-std=c++11
-.endif
 CXXFLAGS+=	-fno-rtti
+CXXSTD=		c++11
 STATIC_CXXFLAGS+= -fvisibility=hidden -fPIC
 # Probably need to just move this earlier or use CXXFLAGS
 .if ${MK_DIRDEPS_BUILD} == "yes"
Index: lib/libomp/Makefile
===================================================================
--- lib/libomp/Makefile
+++ lib/libomp/Makefile
@@ -53,9 +53,9 @@
 CFLAGS+=	-ffunction-sections
 CFLAGS+=	-fdata-sections
 CXXFLAGS+=	-fvisibility-inlines-hidden
-CXXFLAGS+=	-std=c++11
 CXXFLAGS+=	-fno-exceptions
 CXXFLAGS+=	-fno-rtti
+CXXSTD=		c++11
 
 LDFLAGS+=	-Wl,--warn-shared-textrel
 LDFLAGS+=	-Wl,--gc-sections
Index: lib/ofed/libibnetdisc/Makefile
===================================================================
--- lib/ofed/libibnetdisc/Makefile
+++ lib/ofed/libibnetdisc/Makefile
@@ -31,9 +31,6 @@
 CFLAGS+=	-DHAVE_CONFIG_H=1
 CFLAGS+=	-I${_spath}
 CFLAGS+=	-I${SYSROOT:U${DESTDIR}}/${INCLUDEDIR}/infiniband
-.if ${COMPILER_FEATURES:Mc++11}
-CXXFLAGS+=	-std=c++11
-.endif
 VERSION_MAP=	${_spath}/libibnetdisc.map
 
 .include <bsd.lib.mk>
Index: share/mk/bsd.sys.mk
===================================================================
--- share/mk/bsd.sys.mk
+++ share/mk/bsd.sys.mk
@@ -24,6 +24,19 @@
 .else # CSTD
 CFLAGS+=	-std=${CSTD}
 .endif # CSTD
+
+.if ${COMPILER_FEATURES:Mc++11}
+CXXSTD?=	c++11
+.elif ${COMPILER_TYPE} == "gcc"
+# Prior versions of g++ support C++98 with GNU extensions by default.
+CXXSTD?=	gnu++98
+.else
+# Assume that the compiler supports at least C++98.
+CXXSTD?=	c++98
+.endif
+CXXFLAGS+=	-std=${CXXSTD}
+# CXXSTD
+
 # -pedantic is problematic because it also imposes namespace restrictions
 #CFLAGS+=	-pedantic
 .if defined(WARNS)
Index: share/mk/googletest.test.inc.mk
===================================================================
--- share/mk/googletest.test.inc.mk
+++ share/mk/googletest.test.inc.mk
@@ -1,13 +1,9 @@
 # $FreeBSD$
 
-# XXX: this should be defined in bsd.sys.mk
-CXXSTD?=	c++11
-
 GTESTS_CXXFLAGS+= -DGTEST_HAS_POSIX_RE=1
 GTESTS_CXXFLAGS+= -DGTEST_HAS_PTHREAD=1
 GTESTS_CXXFLAGS+= -DGTEST_HAS_STREAM_REDIRECTION=1
 GTESTS_CXXFLAGS+= -frtti
-GTESTS_CXXFLAGS+= -std=${CXXSTD}
 
 # XXX: src.libnames.mk should handle adding this directory for libgtest's,
 # libgmock's, etc, headers.
Index: usr.bin/dtc/Makefile
===================================================================
--- usr.bin/dtc/Makefile
+++ usr.bin/dtc/Makefile
@@ -6,7 +6,7 @@
 
 WARNS?=	3
 
-CXXFLAGS+=	-std=c++11 -fno-rtti -fno-exceptions
+CXXFLAGS+=	-fno-rtti -fno-exceptions
 
 NO_SHARED?=NO
 
Index: usr.sbin/pmc/Makefile
===================================================================
--- usr.sbin/pmc/Makefile
+++ usr.sbin/pmc/Makefile
@@ -6,7 +6,8 @@
 PROG_CXX=	pmc
 MAN=	
 WARNS?=	3
-CXXFLAGS+= -O0 -std=c++14
+CXXFLAGS+= -O0
+CXXSTD= c++14
 CWARNFLAGS.gcc+= -Wno-redundant-decls
 
 LIBADD=	kvm pmc m ncursesw pmcstat elf