I'm not sure this fix is correct (since I'm not entirely sure why C++17
is needed, but maybe abseil/protobuf default to C++17 nowadays).
If this works for you, feel free to commit, otherwise it might provide a
starting point for a better fix.
Index: Makefile
===================================================================
RCS file: /cvs/ports/games/goldberg_emulator/Makefile,v
diff -u -p -r1.7 Makefile
--- Makefile 26 Sep 2023 09:41:36 -0000 1.7
+++ Makefile 18 Nov 2023 01:40:21 -0000
@@ -22,8 +22,9 @@ FIX_CRLF_FILES = sdk_includes/isteamuser
sdk_includes/steamclientpublic.h \
sdk_includes/steam_gameserver.h
-# C++14
+# C++17 (abseil)
COMPILER = base-clang ports-gcc
+CXXFLAGS += -std=c++17
LIB_DEPENDS = devel/protobuf
USE_GMAKE = Yes
Index: patches/patch-Makefile
===================================================================
RCS file: /cvs/ports/games/goldberg_emulator/patches/patch-Makefile,v
diff -u -p -r1.4 patch-Makefile
--- patches/patch-Makefile 11 Mar 2022 19:04:30 -0000 1.4
+++ patches/patch-Makefile 18 Nov 2023 01:23:41 -0000
@@ -14,7 +14,7 @@ Index: Makefile
-CXX_FLAGS += -fPIC -std=c++14
-LD_FLAGS += -shared -lprotobuf-lite -ldl -Wl,--no-undefined
+CXX=c++
-+CXX_FLAGS += ${CXXFLAGS} -fPIC -std=c++14 -I${LOCALBASE}/include
++CXX_FLAGS += ${CXXFLAGS} -fPIC -I${LOCALBASE}/include
+LD_FLAGS += -shared -L${LOCALBASE}/lib -lprotobuf-lite
LIBRARY_NAME=libsteam_api.so
RM = rm -f
