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>

qmake/generators/makefile.cpp

@@ -1212,7 +1212,7 @@ MakefileGenerator::writeInstalls(QTextStream &t, bool noBuild)
         }
 
         bool do_default = true;
-        const QString root = "$(INSTALL_ROOT)";
+        const QString root = installRoot();
         QString dst;
         if (installConfigValues.indexOf("no_path") == -1 &&
             installConfigValues.indexOf("dummy_install") == -1) {

qmake/generators/makefile.h

@@ -192,6 +192,7 @@ protected:
 
     //for installs
     virtual QString defaultInstall(const QString &);
+    virtual QString installRoot() const;
 
     //for prl
     QString prlFileName(bool fixify=true);
@@ -277,6 +278,9 @@ inline bool MakefileGenerator::noIO() const
 inline QString MakefileGenerator::defaultInstall(const QString &)
 { return QString(""); }
 
+inline QString MakefileGenerator::installRoot() const
+{ return QStringLiteral("$(INSTALL_ROOT)"); }
+
 inline bool MakefileGenerator::findLibraries(bool, bool)
 { return true; }
 

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)

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);
 

qmake/generators/win32/mingw_make.cpp

@@ -112,6 +112,18 @@ bool MingwMakefileGenerator::writeMakefile(QTextStream &t)
     return false;
  }
 
+QString MingwMakefileGenerator::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@%=%)");
+}
+
 void createLdObjectScriptFile(const QString &fileName, const ProStringList &objList)
 {
     QString filePath = Option::output_dir + QDir::separator() + fileName;

qmake/generators/win32/mingw_make.h

@@ -50,6 +50,7 @@ protected:
     virtual QString getManifestFileForRcFile() const;
     bool writeMakefile(QTextStream &);
     void init();
+    virtual QString installRoot() const;
 private:
     void writeMingwParts(QTextStream &);
     void writeIncPart(QTextStream &t);

qmake/generators/win32/msvc_nmake.cpp

@@ -268,7 +268,7 @@ QString NmakeMakefileGenerator::defaultInstall(const QString &t)
 
     QString ret = Win32MakefileGenerator::defaultInstall(t);
 
-    const QString root = "$(INSTALL_ROOT)";
+    const QString root = installRoot();
     ProStringList &uninst = project->values(ProKey(t + ".uninstall"));
     QString targetdir = fileFixify(project->first(ProKey(t + ".path")).toQString(), FileFixifyAbsolute);
     if(targetdir.right(1) != Option::dir_sep)

qmake/generators/win32/winmakefile.cpp

@@ -689,7 +689,7 @@ QString Win32MakefileGenerator::defaultInstall(const QString &t)
         project->first("TEMPLATE") == "subdirs" || project->first("TEMPLATE") == "aux")
        return QString();
 
-    const QString root = "$(INSTALL_ROOT)";
+    const QString root = installRoot();
     ProStringList &uninst = project->values(ProKey(t + ".uninstall"));
     QString ret;
     QString targetdir = fileFixify(project->first(ProKey(t + ".path")).toQString(), FileFixifyAbsolute);