diff --git a/x11-libs/neXtaw/files/neXtaw-0.15.1-clang16.patch b/x11-libs/neXtaw/files/neXtaw-0.15.1-clang16.patch
new file mode 100644
index 0000000000000..a1f5bf27922c7
--- /dev/null
+++ b/x11-libs/neXtaw/files/neXtaw-0.15.1-clang16.patch
@@ -0,0 +1,27 @@
+https://bugs.gentoo.org/871489
+--- a/X11/neXtaw/XawIm.c
++++ b/X11/neXtaw/XawIm.c
+@@ -61,2 +61,3 @@
+ #include <X11/StringDefs.h>
++#include <X11/ResourceI.h>
+ #include <X11/Xos.h>
+--- a/X11/neXtaw/laygram.y
++++ b/X11/neXtaw/laygram.y
+@@ -16,2 +16,7 @@
+ 
++%code provides {
++    void yyerror(char *s);
++    int yylex(void);
++}
++
+ %union {
+--- a/X11/neXtaw/laylex.l
++++ b/X11/neXtaw/laylex.l
+@@ -88,2 +88,3 @@
+ 
++void
+ yysetsource(s)
+@@ -94,2 +95,3 @@
+ 
++void
+ yyerror(s)
diff --git a/x11-libs/neXtaw/neXtaw-0.15.1-r3.ebuild b/x11-libs/neXtaw/neXtaw-0.15.1-r4.ebuild
similarity index 53%
rename from x11-libs/neXtaw/neXtaw-0.15.1-r3.ebuild
rename to x11-libs/neXtaw/neXtaw-0.15.1-r4.ebuild
index f89f61178319e..db8f5d2fd8eeb 100644
--- a/x11-libs/neXtaw/neXtaw-0.15.1-r3.ebuild
+++ b/x11-libs/neXtaw/neXtaw-0.15.1-r4.ebuild
@@ -1,34 +1,47 @@
-# Copyright 1999-2021 Gentoo Authors
+# Copyright 1999-2022 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
-EAPI=7
+EAPI=8
+
+inherit flag-o-matic
 
 DESCRIPTION="Athena Widgets with N*XTSTEP appearance"
-HOMEPAGE="http://siag.nu/neXtaw/"
-SRC_URI="http://siag.nu/pub/neXtaw/${P}.tar.gz"
+HOMEPAGE="https://siag.nu/neXtaw/"
+SRC_URI="https://siag.nu/pub/neXtaw/${P}.tar.gz"
 
 LICENSE="BSD"
 SLOT="0"
 KEYWORDS="~alpha amd64 arm arm64 ~hppa ~ia64 ppc ppc64 ~riscv sparc x86 ~amd64-linux ~x86-linux ~ppc-macos ~sparc-solaris"
 
 RDEPEND="
-	x11-base/xorg-proto
 	x11-libs/libICE
-	x11-libs/libXext
-	x11-libs/libXt
-	x11-libs/libX11
 	x11-libs/libSM
+	x11-libs/libX11
+	x11-libs/libXext
 	x11-libs/libXmu
-	x11-libs/libxkbfile
 	x11-libs/libXpm
-	!<x11-libs/neXtaw-0.15.1-r1"
-DEPEND="${RDEPEND}"
+	x11-libs/libXt
+	x11-libs/libxkbfile"
+DEPEND="
+	${RDEPEND}
+	x11-base/xorg-proto"
+BDEPEND="
+	sys-devel/flex
+	virtual/yacc"
+
+PATCHES=(
+	"${FILESDIR}"/${P}-clang16.patch
+)
 
 src_configure() {
-	econf --disable-static
+	append-cflags -std=gnu89 # old codebase, incompatible with c2x
+	append-cflags -fno-strict-aliasing #864535
+
+	default
 }
 
 src_install() {
 	default
+
 	find "${ED}" -name '*.la' -delete || die
 }