Adapt unix Makefile template to 'no-makedepend'

This change is a bit more complex, as it involves several recipe
variants.

Also, remove the $(CROSS_COMPILE) prefix for the makedepend program.
When we use the program "makedepend", this doesn't serve anything,
and when we use the compiler, this value isn't even used.

Reviewed-by: Rich Salz <rsalz@openssl.org>