Work around MinGW-make's magic prefixing of paths.

When building QNX on MS-Windows, make magically adds the Msys root as
prefix to variables whose values look like paths; this applies to both
environment variables and variables given values on the command-line.
When we don't actually want to install under the Msys root, this is
unwelcome "help".  So (for MinGW's make) support a magic prefix of our
own, @msyshack@, that'll make a path value for INSTALL_ROOT not look
like a path to make; we can then strip it off when we come to use it.

Change-Id: I951ad3c8fe3e5cfb49e6e361d7fff779f3a9d716
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@theqtcompany.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@theqtcompany.com>

2 files changed, 18 insertions, 1 deletions

diff --git a/qmake/generators/unix/unixmake.cpp b/qmake/generators/unix/unixmake.cpp
index 57c0a97228..12b9f09edd 100644
--- a/qmake/generators/unix/unixmake.cpp
+++ b/qmake/generators/unix/unixmake.cpp
@@ -514,6 +514,20 @@ UnixMakefileGenerator::findLibraries(bool linkPrl, bool mergeLflags)
     return false;
 }
 
+#ifdef Q_OS_WIN // MinGW x-compiling for QNX
+QString UnixMakefileGenerator::installRoot() const
+{
+    /*
+      We include a magic prefix on the path to bypass mingw-make's "helpful"
+      intervention in the environment, recognising variables that look like
+      paths and adding the msys system root as prefix, which we don't want.
+      Once this hack has smuggled INSTALL_ROOT into make's variable space, we
+      can trivially strip the magic prefix back off to get the path we meant.
+     */
+    return QStringLiteral("$(INSTALL_ROOT:@msyshack@%=%)");
+}
+#endif
+
 QString
 UnixMakefileGenerator::defaultInstall(const QString &t)
 {
@@ -522,7 +536,7 @@ UnixMakefileGenerator::defaultInstall(const QString &t)
 
     enum { NoBundle, SolidBundle, SlicedBundle } bundle = NoBundle;
     bool isAux = (project->first("TEMPLATE") == "aux");
-    const QString root = "$(INSTALL_ROOT)";
+    const QString root = installRoot();
     ProStringList &uninst = project->values(ProKey(t + ".uninstall"));
     QString ret, destdir = project->first("DESTDIR").toQString();
     if(!destdir.isEmpty() && destdir.right(1) != Option::dir_sep)
diff --git a/qmake/generators/unix/unixmake.h b/qmake/generators/unix/unixmake.h
index db3f59f517..17270ffce9 100644
--- a/qmake/generators/unix/unixmake.h
+++ b/qmake/generators/unix/unixmake.h
@@ -52,6 +52,9 @@ public:
 protected:
     virtual bool doPrecompiledHeaders() const { return project->isActiveConfig("precompile_header"); }
     virtual bool doDepends() const { return !Option::mkfile::do_stub_makefile && MakefileGenerator::doDepends(); }
+#ifdef Q_OS_WIN // MinGW x-compiling for QNX
+    virtual QString installRoot() const;
+#endif
     virtual QString defaultInstall(const QString &);
     virtual ProString fixLibFlag(const ProString &lib);