Doc - Using SUBDIRS variable

Task-number: QTCREATORBUG-2430

Reviewed-by: hjk

Reviewed-by: Jarek Kobus

doc/qtcreator.qdoc

@@ -1927,6 +1927,35 @@
 
     This also makes the files available in the \gui Locator.
 
+    \section1 Adding Subprojects to Projects
+
+    When you create a new project, you can add it to another project as a subproject
+    in the \gui{Project Management} dialog. However, you first have to edit the
+    .pro file of the parent project to specify that qmake uses the \c subdirs template
+    to build the project.
+
+    The \c subdirs template creates a Makefile for building subprojects. They can be
+    located either in subdirectories of the project directory or in any other directory.
+    The location of the targets is specified using the SUBDIRS variable. If the project file
+    has the same name as the directory, you can just specify the directory name. If the project
+    name and directory name are different, you must specify the project file name (.pro).
+
+    For more information on the SUBDIRS variable, see the
+    \l{http://doc.qt.nokia.com/4.7/qmake-variable-reference.html#subdirs}{qmake Variable Reference}.
+
+    For example, the following code specifies that plugin_coreplugin/plugin_coreplugin.pro
+    and mylogin.pro belong to the project:
+
+    \code
+    TEMPLATE  = subdirs
+
+    SUBDIRS = plugin_coreplugin \
+    ../another/plugin/myplugin.pro
+    \endcode
+
+    To specify dependencies, use the \gui{Add Library} wizard. For more information,
+    see \l{Adding Libraries to qmake Projects}.
+
 */