Fix some small additional issues when building on modern toolchains

[johnsonjh]

• Tested with:

  • Native: GCC 12.0.1 20220401 (Red Hat 12.0.1-0)
  • OR1K: GCC 5.2.0, binutils 2.26, Newlib 2.3.0 (+or1k backports)

• A friend was having some issues compiling on a modern system ~- hopefully this should fix it; waiting for final test so I don't have to install Quartus.~

• PR https://github.com/rkrajnc/minimig-de1/pull/7 will close.

Edit: Worked.

[johnsonjh]

Added https://github.com/rkrajnc/minimig-de1/pull/7#pullrequestreview-946052628.