Index: head/share/mk/bsd.sys.mk
===================================================================
--- head/share/mk/bsd.sys.mk	(revision 303270)
+++ head/share/mk/bsd.sys.mk	(revision 303271)
@@ -1,319 +1,337 @@
 # $FreeBSD$
 #
 # This file contains common settings used for building FreeBSD
 # sources.
 
 # Enable various levels of compiler warning checks.  These may be
 # overridden (e.g. if using a non-gcc compiler) by defining MK_WARNS=no.
 
 # for GCC:   http://gcc.gnu.org/onlinedocs/gcc-4.2.1/gcc/Warning-Options.html
 
 .include <bsd.compiler.mk>
 
 # the default is gnu99 for now
 CSTD?=		gnu99
 
 .if ${CSTD} == "k&r"
 CFLAGS+=	-traditional
 .elif ${CSTD} == "c89" || ${CSTD} == "c90"
 CFLAGS+=	-std=iso9899:1990
 .elif ${CSTD} == "c94" || ${CSTD} == "c95"
 CFLAGS+=	-std=iso9899:199409
 .elif ${CSTD} == "c99"
 CFLAGS+=	-std=iso9899:1999
 .else # CSTD
 CFLAGS+=	-std=${CSTD}
 .endif # CSTD
 # -pedantic is problematic because it also imposes namespace restrictions
 #CFLAGS+=	-pedantic
 .if defined(WARNS)
 .if ${WARNS} >= 1
 CWARNFLAGS+=	-Wsystem-headers
 .if !defined(NO_WERROR) && !defined(NO_WERROR.${COMPILER_TYPE})
 CWARNFLAGS+=	-Werror
 .endif # !NO_WERROR && !NO_WERROR.${COMPILER_TYPE}
 .endif # WARNS >= 1
 .if ${WARNS} >= 2
 CWARNFLAGS+=	-Wall -Wno-format-y2k
 .endif # WARNS >= 2
 .if ${WARNS} >= 3
 CWARNFLAGS+=	-W -Wno-unused-parameter -Wstrict-prototypes\
 		-Wmissing-prototypes -Wpointer-arith
 .endif # WARNS >= 3
 .if ${WARNS} >= 4
 CWARNFLAGS+=	-Wreturn-type -Wcast-qual -Wwrite-strings -Wswitch -Wshadow\
 		-Wunused-parameter
 .if !defined(NO_WCAST_ALIGN) && !defined(NO_WCAST_ALIGN.${COMPILER_TYPE})
 CWARNFLAGS+=	-Wcast-align
 .endif # !NO_WCAST_ALIGN !NO_WCAST_ALIGN.${COMPILER_TYPE}
 .endif # WARNS >= 4
 # BDECFLAGS
 .if ${WARNS} >= 6
 CWARNFLAGS+=	-Wchar-subscripts -Winline -Wnested-externs -Wredundant-decls\
 		-Wold-style-definition
 .if !defined(NO_WMISSING_VARIABLE_DECLARATIONS)
 CWARNFLAGS.clang+=	-Wmissing-variable-declarations
 .endif
 .if !defined(NO_WTHREAD_SAFETY)
 CWARNFLAGS.clang+=	-Wthread-safety
 .endif
 .endif # WARNS >= 6
 .if ${WARNS} >= 2 && ${WARNS} <= 4
 # XXX Delete -Wuninitialized by default for now -- the compiler doesn't
 # XXX always get it right.
 CWARNFLAGS+=	-Wno-uninitialized
 .endif # WARNS >=2 && WARNS <= 4
 CWARNFLAGS+=	-Wno-pointer-sign
 # Clang has more warnings enabled by default, and when using -Wall, so if WARNS
 # is set to low values, these have to be disabled explicitly.
 .if ${WARNS} <= 6
 CWARNFLAGS.clang+=	-Wno-empty-body -Wno-string-plus-int
 .if ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30400
 CWARNFLAGS.clang+= -Wno-unused-const-variable
 .endif
 .endif # WARNS <= 6
 .if ${WARNS} <= 3
 CWARNFLAGS.clang+=	-Wno-tautological-compare -Wno-unused-value\
 		-Wno-parentheses-equality -Wno-unused-function -Wno-enum-conversion
 .if ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30600
 CWARNFLAGS.clang+=	-Wno-unused-local-typedef
 .endif
 .endif # WARNS <= 3
 .if ${WARNS} <= 2
 CWARNFLAGS.clang+=	-Wno-switch -Wno-switch-enum -Wno-knr-promoted-parameter
 .endif # WARNS <= 2
 .if ${WARNS} <= 1
 CWARNFLAGS.clang+=	-Wno-parentheses
 .endif # WARNS <= 1
 .if defined(NO_WARRAY_BOUNDS)
 CWARNFLAGS.clang+=	-Wno-array-bounds
 .endif # NO_WARRAY_BOUNDS
 .endif # WARNS
 
 .if defined(FORMAT_AUDIT)
 WFORMAT=	1
 .endif # FORMAT_AUDIT
 .if defined(WFORMAT)
 .if ${WFORMAT} > 0
 #CWARNFLAGS+=	-Wformat-nonliteral -Wformat-security -Wno-format-extra-args
 CWARNFLAGS+=	-Wformat=2 -Wno-format-extra-args
 .if ${WARNS} <= 3
 CWARNFLAGS.clang+=	-Wno-format-nonliteral
 .endif # WARNS <= 3
 .if !defined(NO_WERROR) && !defined(NO_WERROR.${COMPILER_TYPE})
 CWARNFLAGS+=	-Werror
 .endif # !NO_WERROR && !NO_WERROR.${COMPILER_TYPE}
 .endif # WFORMAT > 0
 .endif # WFORMAT
 .if defined(NO_WFORMAT) || defined(NO_WFORMAT.${COMPILER_TYPE})
 CWARNFLAGS+=	-Wno-format
 .endif # NO_WFORMAT || NO_WFORMAT.${COMPILER_TYPE}
 
 # GCC 5.2.0
 .if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 50200
-CWARNFLAGS+=	-Wno-error=unused-function -Wno-error=enum-compare -Wno-error=logical-not-parentheses -Wno-error=bool-compare -Wno-error=uninitialized -Wno-error=array-bounds -Wno-error=clobbered -Wno-error=cast-align -Wno-error=extra -Wno-error=attributes -Wno-error=inline -Wno-error=unused-but-set-variable -Wno-error=unused-value -Wno-error=strict-aliasing -Wno-error=address
+CWARNFLAGS+=	-Wno-error=address			\
+		-Wno-error=array-bounds			\
+		-Wno-error=attributes			\
+		-Wno-error=bool-compare			\
+		-Wno-error=cast-align			\
+		-Wno-error=clobbered			\
+		-Wno-error=enum-compare			\
+		-Wno-error=extra			\
+		-Wno-error=inline			\
+		-Wno-error=logical-not-parentheses	\
+		-Wno-error=strict-aliasing		\
+		-Wno-error=uninitialized		\
+		-Wno-error=unused-but-set-variable	\
+		-Wno-error=unused-function		\
+		-Wno-error=unused-value
 .endif
 
 # GCC 6.1.0
 .if ${COMPILER_TYPE} == "gcc" && ${COMPILER_VERSION} >= 60100
-CWARNFLAGS+=	-Wno-error=unused-const-variable= -Wno-error=nonnull-compare -Wno-error=shift-negative-value -Wno-error=misleading-indentation -Wno-error=tautological-compare
+CWARNFLAGS+=	-Wno-error=misleading-indentation	\
+		-Wno-error=nonnull-compare		\
+		-Wno-error=shift-negative-value		\
+		-Wno-error=tautological-compare		\
+		-Wno-error=unused-const-variable
 .endif
 
 # How to handle FreeBSD custom printf format specifiers.
 .if ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30600
 FORMAT_EXTENSIONS=	-D__printf__=__freebsd_kprintf__
 .else
 FORMAT_EXTENSIONS=	-fformat-extensions
 .endif
 
 .if defined(IGNORE_PRAGMA)
 CWARNFLAGS+=	-Wno-unknown-pragmas
 .endif # IGNORE_PRAGMA
 
 # We need this conditional because many places that use it
 # only enable it for some files with CLFAGS.$FILE+=${CLANG_NO_IAS}.
 # unconditionally, and can't easily use the CFLAGS.clang=
 # mechanism.
 .if ${COMPILER_TYPE} == "clang"
 CLANG_NO_IAS=	 -no-integrated-as
 .endif
 CLANG_OPT_SMALL= -mstack-alignment=8 -mllvm -inline-threshold=3\
 		 -mllvm -simplifycfg-dup-ret
 .if ${COMPILER_VERSION} >= 30500 && ${COMPILER_VERSION} < 30700
 CLANG_OPT_SMALL+= -mllvm -enable-gvn=false
 .else
 CLANG_OPT_SMALL+= -mllvm -enable-load-pre=false
 .endif
 CFLAGS.clang+=	 -Qunused-arguments
 .if ${MACHINE_CPUARCH} == "sparc64"
 # Don't emit .cfi directives, since we must use GNU as on sparc64, for now.
 CFLAGS.clang+=	 -fno-dwarf2-cfi-asm
 .endif # SPARC64
 # The libc++ headers use c++11 extensions.  These are normally silenced because
 # they are treated as system headers, but we explicitly disable that warning
 # suppression when building the base system to catch bugs in our headers.
 # Eventually we'll want to start building the base system C++ code as C++11,
 # but not yet.
 CXXFLAGS.clang+=	 -Wno-c++11-extensions
 
 .if ${MK_SSP} != "no" && \
     ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips"
 .if (${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30500) || \
     (${COMPILER_TYPE} == "gcc" && \
      (${COMPILER_VERSION} == 40201 || ${COMPILER_VERSION} >= 40900))
 # Don't use -Wstack-protector as it breaks world with -Werror.
 SSP_CFLAGS?=	-fstack-protector-strong
 .else
 SSP_CFLAGS?=	-fstack-protector
 .endif
 CFLAGS+=	${SSP_CFLAGS}
 .endif # SSP && !ARM && !MIPS
 
 # Allow user-specified additional warning flags, plus compiler and file
 # specific flag overrides, unless we've overriden this...
 .if ${MK_WARNS} != "no"
 CFLAGS+=	${CWARNFLAGS} ${CWARNFLAGS.${COMPILER_TYPE}}
 CFLAGS+=	${CWARNFLAGS.${.IMPSRC:T}}
 .endif
 
 CFLAGS+=	 ${CFLAGS.${COMPILER_TYPE}}
 CXXFLAGS+=	 ${CXXFLAGS.${COMPILER_TYPE}}
 
 AFLAGS+=	${AFLAGS.${.IMPSRC:T}}
 ACFLAGS+=	${ACFLAGS.${.IMPSRC:T}}
 CFLAGS+=	${CFLAGS.${.IMPSRC:T}}
 CXXFLAGS+=	${CXXFLAGS.${.IMPSRC:T}}
 
 .if defined(SRCTOP)
 # Prevent rebuilding during install to support read-only objdirs.
 .if !make(all) && make(install) && empty(.MAKE.MODE:Mmeta)
 CFLAGS+=	ERROR-tried-to-rebuild-during-make-install
 .endif
 .endif
 
 # Tell bmake not to mistake standard targets for things to be searched for
 # or expect to ever be up-to-date.
 PHONY_NOTMAIN = analyze afterdepend afterinstall all beforedepend beforeinstall \
 		beforelinking build build-tools buildconfig buildfiles \
 		buildincludes check checkdpadd clean cleandepend cleandir \
 		cleanobj configure depend distclean distribute exe \
 		files html includes install installconfig installfiles \
 		installincludes lint obj objlink objs objwarn \
 		realinstall tags whereobj
 
 # we don't want ${PROG} to be PHONY
 .PHONY: ${PHONY_NOTMAIN:N${PROG:U}}
 .NOTMAIN: ${PHONY_NOTMAIN:Nall}
 
 .if ${MK_STAGING} != "no"
 .if defined(_SKIP_BUILD) || (!make(all) && !make(clean*))
 _SKIP_STAGING?= yes
 .endif
 .if ${_SKIP_STAGING:Uno} == "yes"
 staging stage_libs stage_files stage_as stage_links stage_symlinks:
 .else
 # allow targets like beforeinstall to be leveraged
 DESTDIR= ${STAGE_OBJTOP}
 .export DESTDIR
 
 .if target(beforeinstall)
 .if !empty(_LIBS) || (${MK_STAGING_PROG} != "no" && !defined(INTERNALPROG))
 staging: beforeinstall
 .endif
 .endif
 
 # normally only libs and includes are staged
 .if ${MK_STAGING_PROG} != "no" && !defined(INTERNALPROG)
 STAGE_DIR.prog= ${STAGE_OBJTOP}${BINDIR}
 
 .if !empty(PROG)
 .if defined(PROGNAME)
 STAGE_AS_SETS+= prog
 STAGE_AS_${PROG}= ${PROGNAME}
 stage_as.prog: ${PROG}
 .else
 STAGE_SETS+= prog
 stage_files.prog: ${PROG}
 STAGE_TARGETS+= stage_files
 .endif
 .endif
 .endif
 
 .if !empty(_LIBS) && !defined(INTERNALLIB)
 .if defined(SHLIBDIR) && ${SHLIBDIR} != ${LIBDIR} && ${_LIBS:Uno:M*.so.*} != ""
 STAGE_SETS+= shlib
 STAGE_DIR.shlib= ${STAGE_OBJTOP}${SHLIBDIR}
 STAGE_FILES.shlib+= ${_LIBS:M*.so.*}
 stage_files.shlib: ${_LIBS:M*.so.*}
 .endif
 
 .if defined(SHLIB_LINK) && commands(${SHLIB_LINK:R}.ld)
 STAGE_AS_SETS+= ldscript
 STAGE_AS.ldscript+= ${SHLIB_LINK:R}.ld
 stage_as.ldscript: ${SHLIB_LINK:R}.ld
 STAGE_DIR.ldscript = ${STAGE_LIBDIR}
 STAGE_AS_${SHLIB_LINK:R}.ld:= ${SHLIB_LINK}
 NO_SHLIB_LINKS=
 .endif
 
 .if target(stage_files.shlib)
 stage_libs: ${_LIBS}
 .if defined(DEBUG_FLAGS) && target(${SHLIB_NAME}.symbols)
 stage_files.shlib: ${SHLIB_NAME}.symbols
 .endif
 .else
 stage_libs: ${_LIBS}
 .endif
 .if defined(SHLIB_NAME) && defined(DEBUG_FLAGS) && target(${SHLIB_NAME}.symbols)
 stage_libs: ${SHLIB_NAME}.symbols
 .endif
 
 .endif
 
 .if !empty(INCS) || !empty(INCSGROUPS) && target(buildincludes)
 .if !defined(NO_BEFOREBUILD_INCLUDES)
 stage_includes: buildincludes
 beforebuild: stage_includes
 .endif
 .endif
 
 .for t in stage_libs stage_files stage_as
 .if target($t)
 STAGE_TARGETS+= $t
 .endif
 .endfor
 
 .if !empty(STAGE_AS_SETS)
 STAGE_TARGETS+= stage_as
 .endif
 
 .if !empty(_LIBS) || (${MK_STAGING_PROG} != "no" && !defined(INTERNALPROG))
 
 .if !empty(LINKS)
 STAGE_TARGETS+= stage_links
 .if ${MAKE_VERSION} < 20131001
 stage_links.links: ${_LIBS} ${PROG}
 .endif
 STAGE_SETS+= links
 STAGE_LINKS.links= ${LINKS}
 .endif
 
 .if !empty(SYMLINKS)
 STAGE_TARGETS+= stage_symlinks
 STAGE_SETS+= links
 STAGE_SYMLINKS.links= ${SYMLINKS}
 .endif
 
 .endif
 
 .include <meta.stage.mk>
 .endif
 .endif
 
 .if defined(META_TARGETS)
 .for _tgt in ${META_TARGETS}
 .if target(${_tgt})
 ${_tgt}: ${META_DEPS}
 .endif
 .endfor
 .endif
Index: head/sys/conf/kern.mk
===================================================================
--- head/sys/conf/kern.mk	(revision 303270)
+++ head/sys/conf/kern.mk	(revision 303271)
@@ -1,236 +1,236 @@
 # $FreeBSD$
 
 #
 # Warning flags for compiling the kernel and components of the kernel:
 #
 CWARNFLAGS?=	-Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes \
 		-Wmissing-prototypes -Wpointer-arith -Winline -Wcast-qual \
 		-Wundef -Wno-pointer-sign ${FORMAT_EXTENSIONS} \
 		-Wmissing-include-dirs -fdiagnostics-show-option \
 		-Wno-unknown-pragmas \
 		${CWARNEXTRA}
 #
 # The following flags are next up for working on:
 #	-Wextra
 
 # Disable a few warnings for clang, since there are several places in the
 # kernel where fixing them is more trouble than it is worth, or where there is
 # a false positive.
 .if ${COMPILER_TYPE} == "clang"
 NO_WCONSTANT_CONVERSION=	-Wno-constant-conversion
 NO_WSHIFT_COUNT_NEGATIVE=	-Wno-shift-count-negative
 NO_WSHIFT_COUNT_OVERFLOW=	-Wno-shift-count-overflow
 NO_WSELF_ASSIGN=		-Wno-self-assign
 NO_WUNNEEDED_INTERNAL_DECL=	-Wno-unneeded-internal-declaration
 NO_WSOMETIMES_UNINITIALIZED=	-Wno-error-sometimes-uninitialized
 NO_WCAST_QUAL=			-Wno-cast-qual
 # Several other warnings which might be useful in some cases, but not severe
 # enough to error out the whole kernel build.  Display them anyway, so there is
 # some incentive to fix them eventually.
 CWARNEXTRA?=	-Wno-error-tautological-compare -Wno-error-empty-body \
 		-Wno-error-parentheses-equality -Wno-error-unused-function \
 		-Wno-error-pointer-sign
 .if ${COMPILER_VERSION} >= 30700
 CWARNEXTRA+=	-Wno-error-shift-negative-value
 .endif
 
 CLANG_NO_IAS= -no-integrated-as
 .if ${COMPILER_VERSION} < 30500
 # XXX: clang < 3.5 integrated-as doesn't grok .codeNN directives
 CLANG_NO_IAS34= -no-integrated-as
 .endif
 .endif
 
 .if ${COMPILER_TYPE} == "gcc"
 .if ${COMPILER_VERSION} >= 40800
 # Catch-all for all the things that are in our tree, but for which we're
 # not yet ready for this compiler.
 CWARNEXTRA?=	-Wno-error=inline -Wno-error=enum-compare -Wno-error=unused-but-set-variable \
 		-Wno-error=aggressive-loop-optimizations -Wno-error=maybe-uninitialized \
 		-Wno-error=array-bounds -Wno-error=address \
 		-Wno-error=cast-qual -Wno-error=sequence-point -Wno-error=attributes \
 		-Wno-error=strict-overflow -Wno-error=overflow
 .if ${COMPILER_VERSION} >= 60100
-CWARNEXTRA+=	-Wno-error=nonnull-compare -Wno-error=shift-overflow=
+CWARNEXTRA+=	-Wno-error=nonnull-compare -Wno-error=shift-overflow
 .endif
 .else
 # For gcc 4.2, eliminate the too-often-wrong warnings about uninitialized vars.
 CWARNEXTRA?=	-Wno-uninitialized
 .endif
 .endif
 
 # External compilers may not support our format extensions.  Allow them
 # to be disabled.  WARNING: format checking is disabled in this case.
 .if ${MK_FORMAT_EXTENSIONS} == "no"
 FORMAT_EXTENSIONS=	-Wno-format
 .elif ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 30600
 FORMAT_EXTENSIONS=	-D__printf__=__freebsd_kprintf__
 .else
 FORMAT_EXTENSIONS=	-fformat-extensions
 .endif
 
 #
 # On i386, do not align the stack to 16-byte boundaries.  Otherwise GCC 2.95
 # and above adds code to the entry and exit point of every function to align the
 # stack to 16-byte boundaries -- thus wasting approximately 12 bytes of stack
 # per function call.  While the 16-byte alignment may benefit micro benchmarks,
 # it is probably an overall loss as it makes the code bigger (less efficient
 # use of code cache tag lines) and uses more stack (less efficient use of data
 # cache tag lines).  Explicitly prohibit the use of FPU, SSE and other SIMD
 # operations inside the kernel itself.  These operations are exclusively
 # reserved for user applications.
 #
 # gcc:
 # Setting -mno-mmx implies -mno-3dnow
 # Setting -mno-sse implies -mno-sse2, -mno-sse3 and -mno-ssse3
 #
 # clang:
 # Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa
 # Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42
 #
 .if ${MACHINE_CPUARCH} == "i386"
 CFLAGS.gcc+=	-mno-align-long-strings -mpreferred-stack-boundary=2
 CFLAGS.clang+=	-mno-aes -mno-avx
 CFLAGS+=	-mno-mmx -mno-sse -msoft-float
 INLINE_LIMIT?=	8000
 .endif
 
 .if ${MACHINE_CPUARCH} == "arm"
 INLINE_LIMIT?=	8000
 .endif
 
 .if ${MACHINE_CPUARCH} == "aarch64"
 # We generally don't want fpu instructions in the kernel.
 CFLAGS += -mgeneral-regs-only
 # Reserve x18 for pcpu data
 CFLAGS += -ffixed-x18
 .endif
 
 .if ${MACHINE_CPUARCH} == "riscv"
 CFLAGS.gcc+=	-mcmodel=medany
 INLINE_LIMIT?=	8000
 .endif
 
 #
 # For sparc64 we want the medany code model so modules may be located
 # anywhere in the 64-bit address space.  We also tell GCC to use floating
 # point emulation.  This avoids using floating point registers for integer
 # operations which it has a tendency to do.
 #
 .if ${MACHINE_CPUARCH} == "sparc64"
 CFLAGS.clang+=	-mcmodel=large -fno-dwarf2-cfi-asm
 CFLAGS.gcc+=	-mcmodel=medany -msoft-float
 INLINE_LIMIT?=	15000
 .endif
 
 #
 # For AMD64, we explicitly prohibit the use of FPU, SSE and other SIMD
 # operations inside the kernel itself.  These operations are exclusively
 # reserved for user applications.
 #
 # gcc:
 # Setting -mno-mmx implies -mno-3dnow
 # Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3 and -mfpmath=387
 #
 # clang:
 # Setting -mno-mmx implies -mno-3dnow and -mno-3dnowa
 # Setting -mno-sse implies -mno-sse2, -mno-sse3, -mno-ssse3, -mno-sse41 and -mno-sse42
 # (-mfpmath= is not supported)
 #
 .if ${MACHINE_CPUARCH} == "amd64"
 CFLAGS.clang+=	-mno-aes -mno-avx
 CFLAGS+=	-mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float \
 		-fno-asynchronous-unwind-tables
 INLINE_LIMIT?=	8000
 .endif
 
 #
 # For PowerPC we tell gcc to use floating point emulation.  This avoids using
 # floating point registers for integer operations which it has a tendency to do.
 # Also explicitly disable Altivec instructions inside the kernel.
 #
 .if ${MACHINE_CPUARCH} == "powerpc"
 CFLAGS+=	-mno-altivec
 CFLAGS.clang+=	-mllvm -disable-ppc-float-in-variadic=true
 CFLAGS.gcc+=	-msoft-float
 INLINE_LIMIT?=	15000
 .endif
 
 #
 # Use dot symbols on powerpc64 to make ddb happy
 #
 .if ${MACHINE_ARCH} == "powerpc64"
 CFLAGS.gcc+=	-mcall-aixdesc
 .endif
 
 #
 # For MIPS we also tell gcc to use floating point emulation
 #
 .if ${MACHINE_CPUARCH} == "mips"
 CFLAGS+=	-msoft-float
 INLINE_LIMIT?=	8000
 .endif
 
 #
 # GCC 3.0 and above like to do certain optimizations based on the
 # assumption that the program is linked against libc.  Stop this.
 #
 CFLAGS+=	-ffreestanding
 
 #
 # The C standard leaves signed integer overflow behavior undefined.
 # gcc and clang opimizers take advantage of this.  The kernel makes
 # use of signed integer wraparound mechanics so we need the compiler
 # to treat it as a wraparound and not take shortcuts.
 # 
 CFLAGS+=	-fwrapv
 
 #
 # GCC SSP support
 #
 .if ${MK_SSP} != "no" && \
     ${MACHINE_CPUARCH} != "arm" && ${MACHINE_CPUARCH} != "mips"
 CFLAGS+=	-fstack-protector
 .endif
 
 #
 # Add -gdwarf-2 when compiling -g. The default starting in clang v3.4
 # and gcc 4.8 is to generate DWARF version 4. However, our tools don't
 # cope well with DWARF 4, so force it to genereate DWARF2, which they
 # understand. Do this unconditionally as it is harmless when not needed,
 # but critical for these newer versions.
 #
 .if ${CFLAGS:M-g} != "" && ${CFLAGS:M-gdwarf*} == ""
 CFLAGS+=	-gdwarf-2
 .endif
 
 CFLAGS+= ${CWARNFLAGS} ${CWARNFLAGS.${.IMPSRC:T}}
 CFLAGS+= ${CFLAGS.${COMPILER_TYPE}} ${CFLAGS.${.IMPSRC:T}}
 
 # Tell bmake not to mistake standard targets for things to be searched for
 # or expect to ever be up-to-date.
 PHONY_NOTMAIN = afterdepend afterinstall all beforedepend beforeinstall \
 		beforelinking build build-tools buildfiles buildincludes \
 		checkdpadd clean cleandepend cleandir cleanobj configure \
 		depend distclean distribute exe \
 		html includes install installfiles installincludes lint \
 		obj objlink objs objwarn \
 		realinstall regress \
 		tags whereobj
 
 .PHONY: ${PHONY_NOTMAIN}
 .NOTMAIN: ${PHONY_NOTMAIN}
 
 CSTD=		c99
 
 .if ${CSTD} == "k&r"
 CFLAGS+=        -traditional
 .elif ${CSTD} == "c89" || ${CSTD} == "c90"
 CFLAGS+=        -std=iso9899:1990
 .elif ${CSTD} == "c94" || ${CSTD} == "c95"
 CFLAGS+=        -std=iso9899:199409
 .elif ${CSTD} == "c99"
 CFLAGS+=        -std=iso9899:1999
 .else # CSTD
 CFLAGS+=        -std=${CSTD}
 .endif # CSTD