jom - the parallel make tool for Windows

It's aimed to be an nmake clone with support for parallel builds.
The project's wiki is here: http://wiki.qt.io/Jom

== How to compile jom ==
Jom is a Qt program. The steps to compile jom on command line are:
    qmake
    nmake

== How to compile jom with cmake ==
We assume that everything we do happens in the folder X:\build-jom 
1. unpack these sources of jom into X:\build-jom\jom
2. add a build directory somewhere - this normally either is a
   directory on the same level as the build directory
   or a subdirectory of the source root directory.
   !!! Do not try to build from within the source directory !!!
3. switch into the build directory and run the following commands:

     X:\build-jom\build> cmake X:\build-jom\jom -G "NMake Makefiles" -DCMAKE_PREFIX_PATH=X:\build-jom -DCMAKE_INSTALL_PREFIX=X:\build-jom\install
     ...

   To take a special version of Qt, append -DQT_QMAKE_EXECUTABLE:PATH=X:\build-jom\qt\bin\qmake.exe .

   Now just run:

     X:\build-jom\build> nmake && nmake install
     ...

   If you want to begin new, just throw away the build dir.

== Running the tests ==
   To build the unit tests in jom, add the option -DJOM_ENABLE_TESTS=ON
   to the cmake line.
   To run the tests, you can simply type

    X:\build-jom\> nmake test
    ...

== Environment variables ==

Like nmake, jom reads default command line arguments from an environment variable: JOMFLAGS.
If JOMFLAGS is not set, MAKEFLAGS is read.
This is useful to set up separate flags for nmake and jom, e.g.
    set MAKEFLAGS=L
    set JOMFLAGS=Lj8

== .SYNC dependents ==

You can use the .SYNC directive on the right side of a description
block definition T to prevent jom from running all of T's dependents
in parallel.
For example the following description block adds further dependencies
between its dependents.

    all: Init Prebuild .SYNC Build .SYNC Postbuild

This adds these additional dependencies:
    Build -> Init Prebuild
    Postbuild -> Build

Now the 'Init' and 'Prebuild' targets are built before 'Build'.