Index: Makefile.inc1
===================================================================
--- Makefile.inc1
+++ Makefile.inc1
@@ -1983,7 +1983,7 @@
 #
 # static libgcc.a prerequisite for shared libc
 #
-_prereq_libs= gnu/lib/libgcc lib/libcompiler_rt
+_prereq_libs= lib/libcompiler_rt
 .if ${MK_SSP} != "no"
 _prereq_libs+= gnu/lib/libssp/libssp_nonshared
 .endif
@@ -1995,7 +1995,6 @@
 #
 _startup_libs=	gnu/lib/csu
 _startup_libs+=	lib/csu
-_startup_libs+=	gnu/lib/libgcc
 _startup_libs+=	lib/libcompiler_rt
 _startup_libs+=	lib/libc
 _startup_libs+=	lib/libc_nonshared
@@ -2003,11 +2002,27 @@
 _startup_libs+=	lib/libcxxrt
 .endif
 
+.if ${MK_LLVM_LIBUNWIND} != "no"
+_prereq_libs+=	lib/libgcc_eh lib/libgcc_s
+_startup_libs+=	lib/libgcc_eh lib/libgcc_s
+
+lib/libgcc_s__L: lib/libc__L
+lib/libgcc_s__L: lib/libc_nonshared__L
+.if ${MK_LIBCPLUSPLUS} != "no"
+lib/libcxxrt__L: lib/libgcc_s__L
+.endif
+
+.else # MK_LLVM_LIBUNWIND == no
+
+_prereq_libs+=	gnu/lib/libgcc
+_startup_libs+=	gnu/lib/libgcc
+
 gnu/lib/libgcc__L: lib/libc__L
 gnu/lib/libgcc__L: lib/libc_nonshared__L
 .if ${MK_LIBCPLUSPLUS} != "no"
 lib/libcxxrt__L: gnu/lib/libgcc__L
 .endif
+.endif
 
 _prebuild_libs=	${_kerberos5_lib_libasn1} \
 		${_kerberos5_lib_libhdb} \
Index: gnu/lib/Makefile
===================================================================
--- gnu/lib/Makefile
+++ gnu/lib/Makefile
@@ -3,8 +3,6 @@
 .include <src.opts.mk>
 
 SUBDIR=			csu
-SUBDIR+=		libgcc
-
 SUBDIR.${MK_DIALOG}+=	libdialog
 SUBDIR.${MK_GCC}+=	libgcov libgomp
 SUBDIR.${MK_SSP}+=	libssp
@@ -19,6 +17,10 @@
 SUBDIR+=		libregex
 .endif
 
+.if ${MK_LLVM_LIBUNWIND} == "no"
+SUBDIR+=		libgcc
+.endif
+
 # libsupc++ uses libstdc++ headers, although 'make includes' should
 # have taken care of that already.
 .if ${MK_GNUCXX} != "no"
Index: gnu/lib/libgcc/Makefile
===================================================================
--- gnu/lib/libgcc/Makefile
+++ gnu/lib/libgcc/Makefile
@@ -74,34 +74,6 @@
 LIB2ADD = $(LIB2FUNCS_EXTRA)
 LIB2ADD_ST = $(LIB2FUNCS_STATIC_EXTRA)
 
-# Additional sources to handle exceptions; overridden by targets as needed.
-.if ${MK_LLVM_LIBUNWIND} != "no"
-
-.PATH: ${COMPILERRTDIR}/lib/builtins
-.PATH: ${UNWINDSRCDIR}
-LIB2ADDEH = gcc_personality_v0.c \
-	int_util.c \
-	Unwind-EHABI.cpp \
-	Unwind-sjlj.c \
-	UnwindLevel1-gcc-ext.c \
-	UnwindLevel1.c \
-	UnwindRegistersRestore.S \
-	UnwindRegistersSave.S \
-	libunwind.cpp
-
-CFLAGS+=	-I${UNWINDINCDIR} -I${.CURDIR} -D_LIBUNWIND_IS_NATIVE_ONLY
-.if empty(CXXFLAGS:M-std=*)
-CXXFLAGS+=	-std=c++11
-.endif
-CXXFLAGS+=	-fno-rtti
-STATIC_CXXFLAGS+= -fvisibility=hidden -fPIC
-.if ${MK_DIRDEPS_BUILD} == "yes"
-# Avoid dependency on lib/libc++
-CFLAGS+=	-I${SRCTOP}/contrib/libc++/include
-.endif
-
-.else # MK_LLVM_LIBUNWIND
-
 .if ${TARGET_CPUARCH} == "arm"
 LIB2ADDEH =	unwind-arm.c libunwind-arm.S pr-support.c unwind-c.c
 .else
@@ -109,8 +81,6 @@
 	unwind-c.c
 .endif
 
-.endif # MK_LLVM_LIBUNWIND
-
 LIB2ADDEHSTATIC = $(LIB2ADDEH)
 LIB2ADDEHSHARED = $(LIB2ADDEH)
 
@@ -202,14 +172,7 @@
 .endif
 
 COMMONHDRS=	tm.h tconfig.h options.h gthr-default.h
-.if ${MK_LLVM_LIBUNWIND} != "no"
-# unwind.h is a generated file when MK_LLVM_LIBUNWIND == "no", and a stale
-# copy may be left behind in OBJDIR when switching, so remove it explicitly.
-beforebuild:
-	@rm -f ${.OBJDIR}/unwind.h
-.else
 COMMONHDRS+=	unwind.h
-.endif
 
 #-----------------------------------------------------------------------
 #
Index: lib/Makefile
===================================================================
--- lib/Makefile
+++ lib/Makefile
@@ -160,6 +160,8 @@
 
 SUBDIR.${MK_EFI}+=	libefivar
 SUBDIR.${MK_LIBTHR}+=	libthr
+SUBDIR.${MK_LLVM_LIBUNWIND}+=	libgcc_eh
+SUBDIR.${MK_LLVM_LIBUNWIND}+=	libgcc_s
 SUBDIR.${MK_NAND}+=	libnandfs
 SUBDIR.${MK_NETGRAPH}+=	libnetgraph
 SUBDIR.${MK_NIS}+=	libypclnt