introduce ability to build projects for the host system

when qmake runs into the new option(host_build) command, it will restart
the project evaluation with a host spec.

the new default host spec is called default-host (gasp!). it is
overridden with the pre-exising -spec / -platform option, while the new
-xspec / -xplatform option overrides the pre-existing default spec.
specifying -spec but not -xspec will set the xspec, too, so the behavior
is backwards-compatible. same for the XQMAKESPEC override read from
.qmake.cache and the environment variable.
the cleaner solution would be adding -hostspec, to be symmetrical with
the override semantics, but that would deviate from configure in turn.

Change-Id: I4297c873780af16ab7928421b434ce0f1d3820da
Reviewed-by: Joerg Bornemann <joerg.bornemann@nokia.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/qmake/generators/makefile.h b/qmake/generators/makefile.h
index 5b64ea68fb..a4ec259bb0 100644
--- a/qmake/generators/makefile.h
+++ b/qmake/generators/makefile.h
@@ -187,7 +187,7 @@ protected:
 
     //subclasses can use these to query information about how the generator was "run"
     QString buildArgs(const QString &outdir=QString());
-    QString specdir(const QString &outdir=QString());
+    QString specdir(const QString &outdir = QString(), int host_build = -1);
 
     virtual QStringList &findDependencies(const QString &file);
     virtual bool doDepends() const { return Option::mkfile::do_deps; }