Modified the behaviour of the EXACT_INPUT option within the
CPPFile helper function. Now named EXACT_NAME, the option
copies the input file to a temporary file. The name of the
temporary file is also passed in by the caller. This
step in necessary in getting the CPP step to correctly
depend on the targets given by the caller
(through EXTRA_DEPS). Also updated the CPP generation of the
kernel_all.i file to reflect the change.
43b7bca872