diff --git a/doc/index.docbook b/doc/index.docbook
index 85516c3..8ecf0cc 100644
--- a/doc/index.docbook
+++ b/doc/index.docbook
@@ -2450,11 +2450,8 @@ installs the module.
 <entry>qtdir</entry>
 <entry>Module setting overrides global</entry>
 <entry>Set this option to set the environment variable <envar>QTDIR</envar> while building.
-You cannot override this setting in a module option. If you do not specify
-this option, it defaults to
-<filename class="directory"><symbol>${source-dir}</symbol>/build/qt</filename>,
-which uses the qt module included in the &kde; source repository.
-You may use a tilde (~) to represent your home directory.
+If you do not specify this option, &kdesrc-build; will assume that &Qt; is
+provided by the operating system.
 </entry>
 </row>
 
diff --git a/kdesrc-build-setup b/kdesrc-build-setup
index 5c437a3..4797a19 100755
--- a/kdesrc-build-setup
+++ b/kdesrc-build-setup
@@ -324,9 +324,9 @@ print $output <<EOF;
     # once. 'kf5-qt5' is the latest KF5 and Qt5-based software.
     branch-group kf5-qt5
 
-    # The path to your Qt installation.
-    qtdir ~/qt5
-#   qtdir /usr # If system Qt
+    # The path to your Qt installation (default is empty, assumes Qt provided
+    # by system)
+#   qtdir ~/qt5
 
     # Install directory for KDE software
     kdedir $installDir
diff --git a/kdesrc-buildrc-kf5-sample b/kdesrc-buildrc-kf5-sample
index 08b7b97..aaa0619 100644
--- a/kdesrc-buildrc-kf5-sample
+++ b/kdesrc-buildrc-kf5-sample
@@ -7,7 +7,8 @@
 global
     branch-group kf5-qt5
     kdedir ~/kde-5 # Where to install KF5-based software
-    qtdir /usr     # Where to find Qt5
+    # Uncomment this and edit value to choose a different Qt5
+#    qtdir /usr     # Where to find Qt5
 
     # Where to download source code. By default the build directory and
     # logs will be kept under this directory as well.
diff --git a/kdesrc-buildrc-sample b/kdesrc-buildrc-sample
index 23cf108..85444f5 100644
--- a/kdesrc-buildrc-sample
+++ b/kdesrc-buildrc-sample
@@ -24,10 +24,8 @@ global
 #
 # This is the Qt installation to use for building/using KDE. The default is
 # to build Qt (see the qt module below). If you wish to use your system's
-# installed Qt (assuming it is recent enough!) then you can set this to the
-# path to your Qt installation. To find the path to your system's Qt, run
-# "qmake -v". Qt will be installed to the path reported (do not include /lib)
-	qtdir ~/qt4  # Default to installing Qt
+# installed Qt (assuming it is recent enough!) then you can leave this unset.
+#	qtdir ~/qt4  # Default to installing Qt
 
 # By default, each source code module is checked out from its latest
 # development version ('master' for git, 'trunk' for subversion).
diff --git a/modules/ksb/Application.pm b/modules/ksb/Application.pm
index 44cfbb0..3e4f9e9 100644
--- a/modules/ksb/Application.pm
+++ b/modules/ksb/Application.pm
@@ -2260,7 +2260,7 @@ sub _installTemplatedFile
                 \s*%>     # remaining whitespace and closing bracket
               }
               {
-                  $ctx->getOption($1, 'module') ||
+                  $ctx->getOption($1, 'module') //
                       croak_runtime("Invalid variable $1")
               }gxe;
               # Replace all matching expressions, use extended regexp w/
diff --git a/modules/ksb/BuildContext.pm b/modules/ksb/BuildContext.pm
index 3e2c3aa..7634043 100644
--- a/modules/ksb/BuildContext.pm
+++ b/modules/ksb/BuildContext.pm
@@ -112,7 +112,7 @@ our %defaultGlobalOptions = (
     "override-build-system"=> "",
     "override-url"         => "",
     "persistent-data-file" => "",
-    "qtdir"                => "$ENV{HOME}/qt4",
+    "qtdir"                => "",
     "remove-after-install" => "none", # { none, builddir, all }
     "source-dir"           => "$ENV{HOME}/kdesrc",
     "svn-server"           => "svn://anonsvn.kde.org/home/kde",
diff --git a/modules/ksb/BuildSystem/Qt4.pm b/modules/ksb/BuildSystem/Qt4.pm
index 5bc5e89..fe3984a 100644
--- a/modules/ksb/BuildSystem/Qt4.pm
+++ b/modules/ksb/BuildSystem/Qt4.pm
@@ -49,6 +49,12 @@ sub configureInternal
 
     my $prefix = $module->getOption('qtdir');
 
+    if (!$prefix)
+    {
+        error ("\tThe b[qtdir] option must be set to determine where to install r[b[$module]");
+        return 0;
+    }
+
     # Some users have added -prefix manually to their flags, they
     # probably shouldn't anymore. :)
 
diff --git a/modules/ksb/Module.pm b/modules/ksb/Module.pm
index ce3975b..d6aa249 100644
--- a/modules/ksb/Module.pm
+++ b/modules/ksb/Module.pm
@@ -647,31 +647,23 @@ sub setupEnvironment
     my $self = assert_isa(shift, 'ksb::Module');
     my $ctx = $self->buildContext();
     my $kdedir = $self->getOption('kdedir');
-    my $qtdir = $self->getOption('qtdir');
     my $prefix = $self->installationPath();
 
-    # Add global set-envs
+    # Add global set-envs and context
     $self->buildContext()->applyUserEnvironment();
 
-    # Add some standard directories for pkg-config support.  Include env settings.
-    my @pkg_config_dirs = ("$kdedir/lib/pkgconfig", "$qtdir/lib/pkgconfig");
+    my @pkg_config_dirs = ("$kdedir/lib/pkgconfig");
     $ctx->prependEnvironmentValue('PKG_CONFIG_PATH', @pkg_config_dirs);
 
-    # Likewise, add standard directories that should be in LD_LIBRARY_PATH.
-    my @ld_dirs = ("$kdedir/lib", "$qtdir/lib", $self->getOption('libpath'));
+    my @ld_dirs = ("$kdedir/lib", $self->getOption('libpath'));
     $ctx->prependEnvironmentValue('LD_LIBRARY_PATH', @ld_dirs);
 
-    my $buildSystem = $self->buildSystem();
-    $buildSystem->prepareModuleBuildEnvironment($ctx, $self, $prefix);
-
-    my @path = ("$kdedir/bin", "$qtdir/bin", $self->getOption('binpath'));
+    my @path = ("$kdedir/bin", $self->getOption('binpath'));
     $ctx->prependEnvironmentValue('PATH', @path);
 
-    # Set up the children's environment.  We use queueEnvironmentVariable since
-    # it won't set an environment variable to nothing.  (e.g, setting QTDIR to
-    # a blank string might confuse Qt or KDE.
-
-    $ctx->queueEnvironmentVariable('QTDIR', $qtdir);
+    # Build system's environment injection
+    my $buildSystem = $self->buildSystem();
+    $buildSystem->prepareModuleBuildEnvironment($ctx, $self, $prefix);
 
     # Read in user environment defines
     $self->applyUserEnvironment() unless $self == $ctx;