Update (really old) email for Ken
Include `string.h` (for `memmove`)
Fix `lvalue required as left operand of assignment` error
Ignore some files
Fix some bit rot
Fix a warning
Larger changes to the Makefile build system

* Better complience to the Filesystem Hierachy Standard
* Set `RPATH` to $(LIBDIR) to allow easier loading of dynlibs
* Include the dynlibs `intinf`, `msocket`, and `munix` in the `world` target