devel/gmake defaults to CC=cc but CXX=g++. It doesn't seem to make sense to mix `cc`, the system C compiler (typically clang-based) with `g++`, the non-system GNU C++ compiler.
I've been routinely running gmake with a `CXX=c++` prefix in order to build various C/C++ projects. Here's a new patch file that fixes the port for me: /usr/ports/devel/gmake/patches/patch-src_default_c ==== Index src/default.c --- src/default.c.orig +++ src/default.c @@ -530,7 +530,7 @@ "OBJC", "gcc", #else "CC", "cc", - "CXX", "g++", + "CXX", "c++", "OBJC", "cc", #endif ==== - Jules -- http://op59.net