This is used as shebang line for installed scripts.
This could be done in a cleaner way by defining a separate Haiku platform file
and overriding some functions there, but for now, this works well enough.
Some tests are broken because it doesn't find a compiler (adding cmd:gcc to
TEST_REQUIRES isn't sufficient it seems, and it would require $secondaryArchSuffix
which isn't available for any arch recipes).
