I was simply missing a very small patch in Makefile.src.

There is no bump needed, as the no_x11 flavor isn't 
affected.

Index: Makefile
===================================================================
RCS file: /build/data/openbsd/cvs/ports/games/nethack/5.0/Makefile,v
diff -u -p -r1.1.1.1 Makefile
--- Makefile	30 Jun 2026 14:59:13 -0000	1.1.1.1
+++ Makefile	11 Jul 2026 16:00:58 -0000
@@ -15,9 +15,14 @@ WANTLIB +=	c curses m lua5.4
 
 # XXX for now I haven't ported the other flavors
 FLAVORS = no_x11
-FLAVOR ?= no_x11
+FLAVOR ?= 
 
-CONFIG =	simple-config
+.if ${FLAVOR} == "no_x11"
+CONFIG = 	simple-config
+.else
+CONFIG =		x-config
+WANTLIB += X11 Xaw Xext Xmu Xt
+.endif
 
 RUN_DEPENDS = games/hackdata
 WRKDIST =	${WRKDIR}/NetHack-$V
@@ -55,6 +60,11 @@ post-install:
 	${INSTALL_DATA} ${WRKSRC}/doc/Guidebook.txt \
 		${PREFIX}/share/doc/nethack-$V/Guidebook.txt
 	ln -s ${TRUEPREFIX}/${GAMEDIR}/recover ${PREFIX}/bin/recover-$V
+.if ${FLAVOR} == ""
+	${INSTALL_DATA_DIR} ${PREFIX}/lib/X11/app-defaults
+	@${INSTALL_DATA} ${WRKSRC}/win/X11/NetHack.ad \
+	    ${PREFIX}/lib/X11/app-defaults/NetHack-$V
+.endif
 .for i in $(MAN)
 	${WRKBUILD}/util/makedefs --grep --input ${WRKSRC}/doc/$i.6 \
 		--output ${PREFIX}/man/man6/$i-$V.6
Index: files/x-config
===================================================================
RCS file: files/x-config
diff -N files/x-config
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ files/x-config	11 Jul 2026 14:50:23 -0000
@@ -0,0 +1,11 @@
+CFLAGS +=-DX11_GRAPHICS -I$(X11BASE)/include
+LFLAGS += -L$(X11BASE)/lib
+
+WINSRC += $(WINX11SRC)
+WINOBJ += $(WINX11OBJ)
+#WINLIB += $(WINX11LIB)
+WINLIB += -lXaw -lXmu -lXext -lXt -lX11
+
+LINKCMD = $(CC)
+
+VARDATND = $(XFILES)
Index: patches/patch-sys_unix_Makefile_src
===================================================================
RCS file: /build/data/openbsd/cvs/ports/games/nethack/5.0/patches/patch-sys_unix_Makefile_src,v
diff -u -p -r1.1.1.1 patch-sys_unix_Makefile_src
--- patches/patch-sys_unix_Makefile_src	30 Jun 2026 14:59:13 -0000	1.1.1.1
+++ patches/patch-sys_unix_Makefile_src	11 Jul 2026 16:01:02 -0000
@@ -1,6 +1,15 @@
 Index: sys/unix/Makefile.src
 --- sys/unix/Makefile.src.orig
 +++ sys/unix/Makefile.src
+@@ -263,7 +263,7 @@ WINX11SRC = ../win/X11/Window.c ../win/X11/dialogs.c .
+ WINX11OBJ = $(TARGETPFX)Window.o $(TARGETPFX)dialogs.o $(TARGETPFX)winX.o \
+ 	$(TARGETPFX)winmap.o $(TARGETPFX)winmenu.o $(TARGETPFX)winmesg.o \
+ 	$(TARGETPFX)winmisc.o $(TARGETPFX)winstat.o $(TARGETPFX)wintext.o \
+-	$(TARGETPFX)winval.o #$(TARGETPFX)tile.o
++	$(TARGETPFX)winval.o $(TARGETPFX)tile.o
+ #
+ # Files for a Qt 3 interface (renamed since nethack 3.6.x)
+ #
 @@ -506,6 +506,7 @@ LUA_VERSION ?=5.4.8
  LUABASE = liblua-$(LUA_VERSION).a
  LUALIB = ../lib/lua/$(LUABASE)
Index: pkg/PLIST
===================================================================
RCS file: /build/data/openbsd/cvs/ports/games/nethack/5.0/pkg/PLIST,v
diff -u -p -r1.1.1.1 PLIST
--- pkg/PLIST	30 Jun 2026 14:59:13 -0000	1.1.1.1
+++ pkg/PLIST	11 Jul 2026 15:59:24 -0000
@@ -34,5 +34,6 @@ ${GAMEDIR}/xlogfile
 @mode
 @man man/man6/nethack-${V}.6
 @man man/man6/recover-${V}.6
+!%%no_x11%%
 share/doc/nethack-${V}/
 share/doc/nethack-${V}/Guidebook.txt