Add placeholder strstream.h file in the workdir, and patch
some of the Makefile.in's to use the workdir in their include path.
Rewriting this port to use ISO C++ would maybe be better, but will make the diff
a lot larger. Also, the tclmidi program doesn't really seem to be actively
maintained anyway.
PR: ports/64310
Submitted by: Dimitry Andric <dimitry@andric.com>