Roll back to copy ellcc to avoid absolute symlink problem.
See https://bugs.gentoo.org/983219

diff -r eb16e65de2c7 Makefile.in.in
--- a/Makefile.in.in	Thu Sep 24 18:42:28 2026 +0100
+++ b/Makefile.in.in	Fri Sep 25 11:02:50 2026 +0100
@@ -429,7 +429,8 @@
 	${INSTALL_PROGRAM} src/${PROGNAME} $(DESTDIR)${bindir}/${PROGNAME}
 	-chmod 0755 $(DESTDIR)${bindir}/${PROGNAME}
 #else
-	cd $(DESTDIR)${bindir} && $(RM) -f ./ellcc && ${LN_S} ${lispdir}/ellcc.elc ellcc
+	${INSTALL_PROGRAM} ${buildlispdir}/ellcc.elc $(DESDTIR)${bindir}/ellcc
+	-chmod 0755 $(DESTDIR)${bindir}/ellcc
 # ifdef CYGWIN
 	${INSTALL_PROGRAM} src/${PROGNAME} $(DESTDIR)${bindir}/${PROGNAME}-${version}.exe
 	-chmod 0755 $(DESTDIR)${bindir}/${PROGNAME}-${version}.exe