[Qt-interest] parallel building Qt on MSYS/MinGW

[Mark Brand]

This question is about building Qt for MinGW under MSYS.

Using MSYS, I am able to build Qt 4.6 Technology Preview 1 
(qt-everywhere-opensource-src-4.6.0-tp1) with the following commands:

     configure.exe ....
     mingw32-make.exe -j 5

The build succeeds, but the "-j" option does not seem to work. The 
source code files are compiled one at a time, instead of in parallel.

However, if I build a subproject separately, the "-j" option seems to 
work as expected.  For example:

     cd src/sql
     mingw32-make.exe -j 5

Can somebody tell me why this is? I'm not sure if this something I don't 
understand about make, mingw, the Qt makefiles, or something else.

(I posted a similar question in the Qt-creator list yesterday, but I 
hadn't discovered yet that I could parallel build individual subprojects.)

Thanks.