update build instructions in README

README.txt

@@ -24,7 +24,7 @@ Required dependencies for Bluecherry client are:
 - Qt 5
 - SDL 2.0.5 or newer
 - FFmpeg 4.0 or newer
-- MPV
+- MPV (libmpv library)
 
 
 
@@ -52,3 +52,42 @@ git clone https://github.com/bluecherrydvr/bluecherry-client.git
 cd bluecherry-client
 debuild -uc -us -sn -b
 
+Building for Windows.
+=========================
+
+Preferable way of building is cross-compiling on a GNU/Linux host
+using MinGW compiler. MXE project provides convenient way
+of building MinGW cross-toolchain and many opensource libraries
+required as dependencies.
+
+1. Make sure MXE requirements are installed on your host system.
+See https://mxe.cc/#requirements
+
+2. Download Bluecherry sources and build dependencies, Bluecherry
+client .exe and Windows installer using provided helper script:
+
+git clone https://github.com/bluecherrydvr/bluecherry-client.git
+cd bluecherry-client
+./autogen.sh
+cd win
+./cross_build_mxe.sh
+
+Once build is complete (may take few hours), installer executables
+should be located in
+win/mxe/build_installer_i686-w64-mingw32.shared/
+and
+win/mxe/build_installer_x86_64-w64-mingw32.shared/
+for 32 and 64 bit Windows respectively.
+
+Building for OS X.
+=========================
+
+Dependencies can be provided by Macports, Homebrew
+or you can build them yourself.
+
+After the configure and make steps, run
+
+make deploy
+
+to create .dmg package file.
+