the following diff add a patch file used only when using clang, so it links to
c++abi correctly.
Thanks to naddy@ for his explanations about the work required for fixing it.
I found the PATCH_LIST idea from games/xkobo
Index: Makefile
===================================================================
RCS file: /data/cvs/ports/games/tome4/Makefile,v
retrieving revision 1.18
diff -u -p -r1.18 Makefile
--- Makefile 4 Sep 2018 12:46:13 -0000 1.18
+++ Makefile 29 Oct 2018 11:54:13 -0000
@@ -52,6 +52,7 @@ COMPILER_LANGS = c
.include <bsd.port.arch.mk>
.if ${PROPERTIES:Mclang}
WANTLIB-main += c++abi
+PATCH_LIST = patch-* clang-linking
.endif
NO_TEST = Yes
Index: patches/clang-linking
===================================================================
RCS file: patches/clang-linking
diff -N patches/clang-linking
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ patches/clang-linking 29 Oct 2018 12:06:16 -0000
@@ -0,0 +1,15 @@
+$OpenBSD: patch-build_te4core_lua,v 1.2 2018/04/29 10:21:35 solene Exp $
+
+add c++abi to the linker
+
+Index: build/te4core.lua
+--- build/te4core.lua.orig
++++ build/te4core.lua
+@@ -50,6 +50,7 @@ project "TEngine"
+ if _OPTIONS.relpath == "64" then defines{"TE4_RELPATH64"} end
+
+ links { "m" }
++ links { "c++abi" }
+
+ if _OPTIONS.no_rwops_size then defines{"NO_RWOPS_SIZE"} end
+
