add support for a super cache

qmake will now look for .qmake.super, just like it looks for .qmake.cache,
and the cache() function has a mode to write this super cache.
this allows the creation of aggregator projects like, say, qt5.
a notable difference to the normal cache is that this file is *not* added
as a dependency of the Makefile. this means that modifications done by
later sub-projects will not cause a re-processing of earlier projects, and
consequently that one should be cautious regarding what information to
store there.
another notable difference is that this file is read *before* the spec,
so the spec can use the variables from the cache without resorting to
$$fromfile() & co.

Change-Id: I4807b6d34014261fa9eebd6f0ae128b802d86691
Reviewed-by: Joerg Bornemann <joerg.bornemann@nokia.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/qmake/project.h b/qmake/project.h
index e31adc8388..e733f6097c 100644
--- a/qmake/project.h
+++ b/qmake/project.h
@@ -84,6 +84,7 @@ class QMakeProject
     bool own_prop;
     bool backslashWarned;
     QString conffile;
+    QString superfile;
     QString cachefile;
     QString pfile;
     QMakeProperty *prop;