My first contact with CDE was on sparc so it is a shame that sparc64
lacks the packages.
This just needs ports-gcc for C++11 and then it compiles. I did not test
it yet :)

-- 
:wq Claudio

Index: Makefile
===================================================================
RCS file: /cvs/ports/x11/cde/Makefile,v
diff -u -p -r1.19 Makefile
--- Makefile	20 Nov 2025 08:15:54 -0000	1.19
+++ Makefile	25 Nov 2025 10:16:44 -0000
@@ -31,6 +31,9 @@ WANTLIB += ${COMPILER_LIBCXX} ICE Mrm SM
 WANTLIB += Xft Xinerama Xm Xmu Xpm Xrender Xss Xt c expat fontconfig
 WANTLIB += freetype iconv jpeg lmdb m png tcl86 util xcb z
 
+# needs C++11
+COMPILER=		base-clang ports-gcc
+
 MODULES=		lang/tcl
 
 MODTCL_VERSION=		8.6