Clean up build script

Remove loading of thread modules. Not core module, and we don't use
them.

Return value of system command.

Add --force-qmake option, and by default avoid running qmake when a
Makefile already exists.

Do not pass '-j 1' unless explicit on the command line, and pick up
'MAKE' environment variable. (Thiago)

Remove usage of File::Which, as it's not a core module, and often not
present on host machines. (Peppe)

Remove '-s' or '/s' optin to make/nmake, as we cannot see how far we
have compiled, and we only get warnings/errors.

Change the qtwebkit build command, and add separate command for
installing qtwebkit. Also add the required build tools for WebKit
on Windows.

Change-Id: I79bffa39a13ece78fa401f39a38a1ccaf0f389b0

build.dependencies

@@ -19,7 +19,7 @@ use Config;
     "qtimageformats" => "qtbase",
     "qtjsbackend" => "qtbase",
     "qtjsondb" => "qtbase,qtdeclarative,qtxmlpatterns",
-    "qtlocation" => "qtbase,qtdeclarative,qt3d,qtjsondb",
+    "qtlocation" => "qtbase,qtdeclarative,qt3d,qtjsondb:s",
     "qtmultimedia" => "qtbase,qtdeclarative",
     "qtphonon" => "qtbase",
     "qtpim" => "qtdeclarative,qtjsondb:s",
@@ -36,14 +36,24 @@ use Config;
     "qtxmlpatterns" => "qtbase",
 );
 
-%build_commands = (
-    "qtwebkit" => "QMAKEPATH=Tools/qmake qmake && make",
+if ("$Config{osname}" =~ /mswin/i) {
+    %build_commands = (
+        "qtwebkit" => "perl Tools/Scripts/build-webkit --qt --no-netscape-plugin --no-webkit2",
+    );
+} else {
+    %build_commands = (
+        "qtwebkit" => "perl Tools/Scripts/build-webkit --qt --release --no-netscape-plugin",
+    );
+}
+
+%install_commands = (
+    "qtwebkit" => "perl Tools/Scripts/build-webkit --qt --makeargs=\"install\"",
 );
 
 # Platform specific modules
 
 if ("$Config{osname}" =~ /linux/i) {
-    $build_dependencies{"qtwaysland"} = "qtbase";
+    $build_dependencies{"qtwayland"} = "qtbase";
 }
 
 if ("$Config{osname}" =~ /(ms|cyg)win/i) {