diff --git a/sys/conf/files b/sys/conf/files
index 6c0373eec3db..c08e40c469ba 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -1141,7 +1141,7 @@ dev/cxgb/sys/uipc_mvec.c	optional cxgb pci \
 dev/cxgb/cxgb_t3fw.c		optional cxgb cxgb_t3fw \
 	compile-with "${NORMAL_C} -I$S/dev/cxgb"
 dev/cxgbe/t4_mp_ring.c		optional cxgbe pci \
-	compile-with "${NORMAL_C} -I$S/dev/cxgbe ${GCC_MS_EXTENSIONS}"
+	compile-with "${NORMAL_C} -I$S/dev/cxgbe"
 dev/cxgbe/t4_main.c		optional cxgbe pci \
 	compile-with "${NORMAL_C} -I$S/dev/cxgbe"
 dev/cxgbe/t4_netmap.c		optional cxgbe pci \
diff --git a/sys/conf/kern.mk b/sys/conf/kern.mk
index 4317de56c65e..340da8c83fa0 100644
--- a/sys/conf/kern.mk
+++ b/sys/conf/kern.mk
@@ -39,7 +39,6 @@ CLANG_NO_IAS34= -no-integrated-as
 .endif
 
 .if ${COMPILER_TYPE} == "gcc"
-GCC_MS_EXTENSIONS= -fms-extensions
 .if ${COMPILER_VERSION} >= 40300
 # Catch-all for all the things that are in our tree, but for which we're
 # not yet ready for this compiler. Note: we likely only really "support"
diff --git a/sys/conf/kern.pre.mk b/sys/conf/kern.pre.mk
index 232d88b69e82..ede4ae852cf8 100644
--- a/sys/conf/kern.pre.mk
+++ b/sys/conf/kern.pre.mk
@@ -97,7 +97,7 @@ CFLAGS_PARAM_LARGE_FUNCTION_GROWTH?=1000
 .if ${MACHINE_CPUARCH} == "mips"
 CFLAGS_ARCH_PARAMS?=--param max-inline-insns-single=1000
 .endif
-CFLAGS.gcc+= -fno-common -finline-limit=${INLINE_LIMIT}
+CFLAGS.gcc+= -fno-common -fms-extensions -finline-limit=${INLINE_LIMIT}
 CFLAGS.gcc+= --param inline-unit-growth=${CFLAGS_PARAM_INLINE_UNIT_GROWTH}
 CFLAGS.gcc+= --param large-function-growth=${CFLAGS_PARAM_LARGE_FUNCTION_GROWTH}
 .if defined(CFLAGS_ARCH_PARAMS)
@@ -162,7 +162,7 @@ NORMAL_LINT=	${LINT} ${LINTFLAGS} ${CFLAGS:M-[DIU]*} ${.IMPSRC}
 # Infiniband C flags.  Correct include paths and omit errors that linux
 # does not honor.
 OFEDINCLUDES=	-I$S/ofed/include/
-OFEDNOERR=	-Wno-cast-qual -Wno-pointer-arith ${GCC_MS_EXTENSIONS}
+OFEDNOERR=	-Wno-cast-qual -Wno-pointer-arith
 OFEDCFLAGS=	${CFLAGS:N-I*} ${OFEDINCLUDES} ${CFLAGS:M-I*} ${OFEDNOERR}
 OFED_C_NOIMP=	${CC} -c -o ${.TARGET} ${OFEDCFLAGS} ${WERROR} ${PROF}
 OFED_C=		${OFED_C_NOIMP} ${.IMPSRC}
diff --git a/sys/conf/kmod.mk b/sys/conf/kmod.mk
index 8e00aa48e100..91d4f494d3c1 100644
--- a/sys/conf/kmod.mk
+++ b/sys/conf/kmod.mk
@@ -105,6 +105,7 @@ CFLAGS+=	-I. -I${SYSDIR}
 CFLAGS+=	-I${SYSDIR}/contrib/altq
 
 CFLAGS.gcc+=	-finline-limit=${INLINE_LIMIT}
+CFLAGS.gcc+=	-fms-extensions
 CFLAGS.gcc+= --param inline-unit-growth=100
 CFLAGS.gcc+= --param large-function-growth=1000
 
diff --git a/sys/modules/cxgbe/if_cxgbe/Makefile b/sys/modules/cxgbe/if_cxgbe/Makefile
index 32347f468b1e..a66e45a045f4 100644
--- a/sys/modules/cxgbe/if_cxgbe/Makefile
+++ b/sys/modules/cxgbe/if_cxgbe/Makefile
@@ -26,4 +26,3 @@ SRCS+=	t4_tracer.c
 CFLAGS+= -I${CXGBE}
 
 .include <bsd.kmod.mk>
-CFLAGS+= ${GCC_MS_EXTENSIONS}
diff --git a/sys/modules/drm2/radeonkms/Makefile b/sys/modules/drm2/radeonkms/Makefile
index 076b8256e936..1e674a748e96 100644
--- a/sys/modules/drm2/radeonkms/Makefile
+++ b/sys/modules/drm2/radeonkms/Makefile
@@ -106,6 +106,6 @@ SRCS	+=								\
 	iicbus_if.h							\
 	pci_if.h
 
-CFLAGS  += -I${.CURDIR}/../../../dev/drm2/radeon ${GCC_MS_EXTENSIONS}
+CFLAGS  += -I${.CURDIR}/../../../dev/drm2/radeon
 
 .include <bsd.kmod.mk>
diff --git a/sys/modules/ibcore/Makefile b/sys/modules/ibcore/Makefile
index 6a471d254747..60ec8dd3cace 100644
--- a/sys/modules/ibcore/Makefile
+++ b/sys/modules/ibcore/Makefile
@@ -18,6 +18,6 @@ CFLAGS+= -DINET6 -DINET
 
 .include <bsd.kmod.mk>
 
-CFLAGS+= -Wno-cast-qual -Wno-pointer-arith ${GCC_MS_EXTENSIONS}
+CFLAGS+= -Wno-cast-qual -Wno-pointer-arith
 
 CWARNFLAGS.cm.c=	-Wno-unused-function
diff --git a/sys/modules/ipoib/Makefile b/sys/modules/ipoib/Makefile
index d634e375899a..ba8c6d35a6ac 100644
--- a/sys/modules/ipoib/Makefile
+++ b/sys/modules/ipoib/Makefile
@@ -15,4 +15,4 @@ CFLAGS+= -DINET6 -DINET
 
 .include <bsd.kmod.mk>
 
-CFLAGS+= -Wno-cast-qual -Wno-pointer-arith ${GCC_MS_EXTENSIONS}
+CFLAGS+= -Wno-cast-qual -Wno-pointer-arith
diff --git a/sys/modules/mlx4/Makefile b/sys/modules/mlx4/Makefile
index d989ff05ae78..cd2b177f13b4 100644
--- a/sys/modules/mlx4/Makefile
+++ b/sys/modules/mlx4/Makefile
@@ -15,7 +15,6 @@ CFLAGS+= -I${.CURDIR}/../../ofed/include/
 
 .include <bsd.kmod.mk>
 
-CFLAGS+= -Wno-cast-qual -Wno-pointer-arith ${GCC_MS_EXTENSIONS}
-CFLAGS+= -fms-extensions
+CFLAGS+= -Wno-cast-qual -Wno-pointer-arith
 
 CWARNFLAGS.mcg.c=	-Wno-unused
diff --git a/sys/modules/mlx4ib/Makefile b/sys/modules/mlx4ib/Makefile
index 4ab7a4e7f338..7bfcb4a61a5a 100644
--- a/sys/modules/mlx4ib/Makefile
+++ b/sys/modules/mlx4ib/Makefile
@@ -13,8 +13,7 @@ CFLAGS+= -I${.CURDIR}/../../ofed/drivers/infiniband/hw/mlx4
 CFLAGS+= -I${.CURDIR}/../../ofed/include/
 CFLAGS+= -DCONFIG_INFINIBAND_USER_MEM
 CFLAGS+= -DINET6 -DINET
-CFLAGS+= -fms-extensions
 
 .include <bsd.kmod.mk>
 
-CFLAGS+= -Wno-cast-qual -Wno-pointer-arith ${GCC_MS_EXTENSIONS}
+CFLAGS+= -Wno-cast-qual -Wno-pointer-arith
diff --git a/sys/modules/mlxen/Makefile b/sys/modules/mlxen/Makefile
index 258cf7e7bf98..02f777659fcb 100644
--- a/sys/modules/mlxen/Makefile
+++ b/sys/modules/mlxen/Makefile
@@ -8,8 +8,7 @@ SRCS	+= en_rx.c en_tx.c utils.c
 SRCS	+= opt_inet.h opt_inet6.h
 CFLAGS+= -I${.CURDIR}/../../ofed/drivers/net/mlx4
 CFLAGS+= -I${.CURDIR}/../../ofed/include/
-CFLAGS+= -fms-extensions
 
 .include <bsd.kmod.mk>
 
-CFLAGS+= -Wno-cast-qual -Wno-pointer-arith ${GCC_MS_EXTENSIONS}
+CFLAGS+= -Wno-cast-qual -Wno-pointer-arith
diff --git a/sys/modules/mthca/Makefile b/sys/modules/mthca/Makefile
index 25daedb0e3d3..31fcebd1828e 100644
--- a/sys/modules/mthca/Makefile
+++ b/sys/modules/mthca/Makefile
@@ -14,4 +14,4 @@ CFLAGS+= -I${.CURDIR}/../../ofed/include
 
 .include <bsd.kmod.mk>
 
-CFLAGS+= -Wno-cast-qual -Wno-pointer-arith ${GCC_MS_EXTENSIONS}
+CFLAGS+= -Wno-cast-qual -Wno-pointer-arith
diff --git a/sys/ofed/drivers/net/mlx4/Makefile b/sys/ofed/drivers/net/mlx4/Makefile
index dc0e2a374112..05338e804fa2 100644
--- a/sys/ofed/drivers/net/mlx4/Makefile
+++ b/sys/ofed/drivers/net/mlx4/Makefile
@@ -30,4 +30,4 @@ opt_inet6.h:
 
 .include <bsd.kmod.mk>
 
-CFLAGS+= -Wno-cast-qual -Wno-pointer-arith ${GCC_MS_EXTENSIONS}
+CFLAGS+= -Wno-cast-qual -Wno-pointer-arith