diff --git a/devel/wasi-libc/Makefile b/devel/wasi-libc/Makefile
--- a/devel/wasi-libc/Makefile
+++ b/devel/wasi-libc/Makefile
@@ -1,5 +1,5 @@
 PORTNAME=	wasi-libc
-DISTVERSION=	g20201005
+DISTVERSION=	g20210923
 CATEGORIES=	devel
 
 MAINTAINER=	greg@unrelenting.technology
@@ -18,10 +18,10 @@
 USES=		gmake
 USE_GITHUB=	yes
 GH_ACCOUNT=	WebAssembly
-GH_TAGNAME=	9083fe84568fb4de76152757abfd216ba34ad908
-GH_TUPLE=	WebAssembly:WASI:54a8be9:wasi/tools/wasi-headers/WASI
+GH_TAGNAME=	ad5133410f66b93a2381db5b542aad5e0964db96
+GH_TUPLE=	WebAssembly:WASI:ef8c1a53fe:wasi/tools/wasi-headers/WASI
 NO_ARCH=	yes
-LLVM_VERSION?=	11
+LLVM_VERSION?=	13
 
 ALL_TARGET=	finish
 
@@ -34,7 +34,7 @@
 MAKE_ENV=	INSTALL_DIR=${STAGEDIR}${WASI_SYSROOT} \
 		WASM_AR=${LOCALBASE}/bin/llvm-ar${LLVM_VERSION} \
 		WASM_CC=${LOCALBASE}/bin/clang${LLVM_VERSION} \
-		WASM_CFLAGS="-O2 -DNDEBUG -I${FILESDIR}" \
+		WASM_CFLAGS="-O2 -DNDEBUG -isystem ${FILESDIR}" \
 		WASM_NM=${LOCALBASE}/bin/llvm-nm${LLVM_VERSION}
 
 # NOTE: phony targets cause make install to rebuild everything
diff --git a/devel/wasi-libc/distinfo b/devel/wasi-libc/distinfo
--- a/devel/wasi-libc/distinfo
+++ b/devel/wasi-libc/distinfo
@@ -1,5 +1,5 @@
-TIMESTAMP = 1603452634
-SHA256 (WebAssembly-wasi-libc-g20201005-9083fe84568fb4de76152757abfd216ba34ad908_GH0.tar.gz) = 9311ab7117b26bda1bc7ae98335ea85186f769beba21bb2718b943c9eaaf7818
-SIZE (WebAssembly-wasi-libc-g20201005-9083fe84568fb4de76152757abfd216ba34ad908_GH0.tar.gz) = 1222481
-SHA256 (WebAssembly-WASI-54a8be9_GH0.tar.gz) = 88dc40a1919223f16ce2e495a05c72991f2aa39d0ada1a89abf069f914517a6c
-SIZE (WebAssembly-WASI-54a8be9_GH0.tar.gz) = 273430
+TIMESTAMP = 1633602535
+SHA256 (WebAssembly-wasi-libc-g20210923-ad5133410f66b93a2381db5b542aad5e0964db96_GH0.tar.gz) = 085ab45e0591041a8dc104978ad3ff72589072161a922011762d53bf07169ac2
+SIZE (WebAssembly-wasi-libc-g20210923-ad5133410f66b93a2381db5b542aad5e0964db96_GH0.tar.gz) = 1251318
+SHA256 (WebAssembly-WASI-ef8c1a53fe_GH0.tar.gz) = 38be36dc47d79f60aadd1bb3deff391594ff6797260c4810cec0e781ad90ec3c
+SIZE (WebAssembly-WASI-ef8c1a53fe_GH0.tar.gz) = 334921
diff --git a/devel/wasi-libc/pkg-plist b/devel/wasi-libc/pkg-plist
--- a/devel/wasi-libc/pkg-plist
+++ b/devel/wasi-libc/pkg-plist
@@ -191,6 +191,7 @@
 share/wasi-sysroot/include/wasi/api.h
 share/wasi-sysroot/include/wasi/libc-environ.h
 share/wasi-sysroot/include/wasi/libc-find-relpath.h
+share/wasi-sysroot/include/wasi/libc-nocwd.h
 share/wasi-sysroot/include/wasi/libc.h
 share/wasi-sysroot/include/wchar.h
 share/wasi-sysroot/include/wctype.h
@@ -208,7 +209,9 @@
 share/wasi-sysroot/lib/wasm32-wasi/libresolv.a
 share/wasi-sysroot/lib/wasm32-wasi/librt.a
 share/wasi-sysroot/lib/wasm32-wasi/libutil.a
+share/wasi-sysroot/lib/wasm32-wasi/libwasi-emulated-getpid.a
 share/wasi-sysroot/lib/wasm32-wasi/libwasi-emulated-mman.a
+share/wasi-sysroot/lib/wasm32-wasi/libwasi-emulated-process-clocks.a
 share/wasi-sysroot/lib/wasm32-wasi/libwasi-emulated-signal.a
 share/wasi-sysroot/lib/wasm32-wasi/libxnet.a
 share/wasi-sysroot/share/wasm32-wasi/defined-symbols.txt