build: Generate multi-target dependencies for sub-packages

Some SRPMs generate multiple sub-packages.   There should only be one
build rule for each such package, with dependencies showing that one
invocation of mock generates all the sub-packages.   This way, when
make is asked to build all the sub-packages, it knows that it only
has to run mock once.

Signed-off-by: Euan Harris <euan.harris@citrix.com>
build: Reduce the amount of output from the makefile

Some stages of the build can produce an enormous amount of
output, which makes it hard to see what's going on.   This
change causes make to echo just the name of the command it
is running and the target it is building.   The commands
will still write error messages to standard output if they
fail.

Signed-off-by: Euan Harris <euan.harris@citrix.com>
build: Don't override the built-in RPM dependency generator

Four ocaml packages overrode RPM's dependency generator.
This upset some other packages that depended on them, when
not building in a clean mock environment.    RPM's builtin
dependency generator seems to be doing a fine job, so we don't
need this override.

Signed-off-by: Euan Harris <euan.harris@citrix.com>