The change to the method of passing compiler flags into the Xen build
system in 6b697676 omitted passing the compiler flags for improving
build reproducibility, so this commit returns them and includes a change
to use the -ffile-prefix-map compiler option to remove host filesystem
artefacts instead of the prior method of redefining the __FILE__ builtin
macro.
Signed-off-by: Christopher Clark <christopher.w.clark@gmail.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>
e57cf80d54