assemble the tool commands at use time, after all

the precise syntax depends on what exactly the command is used for, so
we need to resolve it at the last moment. see followup commits.

This logically reverts commits 6f4ff81380862ad0e788151b35d742f548241d5a
and 731e6bece5cebe205ca47c1c078c7ac18984ba1c.

Change-Id: If285c91d7521069be86d32593b5c2ae2027b3038
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
fix command over-escaping in vcproj files

the vs ide executes the commands verbatim, so they must not be
make-escaped.

Task-number: QTBUG-31289
Change-Id: Ie73fd5c4da5527c2d10bc94ccdf60f8a1ca21351
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
always $-escape make commands

nmake needs %-escaping in addition to $-escaping, not instead.
this has little practical impact, so it went unnoticed.

Change-Id: I144b6142eec0151d83a22e0ac5ead7b0415cdafa
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
fix rcc & uic .depend_commands

unlike the .command, the .depend_command is not executed by make via its
chosen shell, but qmake itself via the system's native shell.
consequently, it needs different path separators and no make-escaping.

Task-number: QTBUG-31289
Change-Id: I480f815753632db6e8d4725f463f8a1fc59680a6
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
make Makefiles not depend on .qmake.super

this avoids that an empty rebuild after a complete build re-runs qmake
everywhere again.

according to 1f83f0cf2a this is the behavior i originally intended,
but somehow it got lost when switching to the new interpreter.

Change-Id: Id5158d7e272fdee4f4a041fb7c828295a0a86684
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>