As found by thfr, der-ascii fails to build if there is no
${DISTDIR}/go_modules on the build machine.

===>  Configuring for der-ascii-0.8.0v0
/bin/sh: cd: /usr/ports/distfiles/go_modules - No such file or directory

I think go.port.mk should not assume this dir exists. One way to work
around this is the below, but perhaps there are better ideas.

I have only lightly tested this and will of course run it through a bulk.

Index: go.port.mk
===================================================================
RCS file: /cvs/ports/lang/go/go.port.mk,v
diff -u -p -r1.101 go.port.mk
--- go.port.mk	19 Jul 2026 10:06:32 -0000	1.101
+++ go.port.mk	11 Aug 2026 07:31:12 -0000
@@ -129,11 +129,14 @@ WRKSRC ?=		${MODGO_WORKSPACE}/src/${ALL_
 MODGO_SETUP_WORKSPACE =	mkdir -p ${WRKSRC:H}; mv ${MODGO_SUBDIR} ${WRKSRC};
 .else
 WRKSRC ?=		${WRKDIR}/${MODGO_MODNAME}@${MODGO_VERSION}
-MODGO_SETUP_WORKSPACE =	ln -sf ${WRKSRC} ${WRKDIR}/${MODGO_MODNAME}; \
+MODGO_SETUP_WORKSPACE =	ln -sf ${WRKSRC} ${WRKDIR}/${MODGO_MODNAME}
+. if !empty(_MODGO_SETUP)
+MODGO_SETUP_WORKSPACE += ; \
 	cd ${DISTDIR}/${MODGO_DIST_SUBDIR}; \
 	for m in ${_MODGO_SETUP}; do \
 	    ${INSTALL} -D $$m ${WRKDIR}/${MODGO_DIST_SUBDIR}/$$m; \
 	done
+. endif
 .endif
 
 INSTALL_STRIP =