If a directory is renamed or deleted before 'make clean', git will
delete the Makefile but leave all of the object and dependency files
around. When make would try to recurse into that directory from the
wildcard, it would error out since there is no Makefile.
Allow everything to be built from the top level directory with just
'make', cleaned with 'make clean', and installed with 'make
install'. Also support these in any particular subdirectory.
Specifying 'make VERBOSE=1' will print each ld/g++/etc. command as
it runs.
Kernel and early host tools (IPCCompiler, etc.) are built as
object.host.o so that they don't conflict with other things built
with the cross-compiler.
