[QBS] Strange incremental build in QtC 3.2 qbs.

[Smirnov Vladimir]

Hi everyone,

I have now strange bug (maybe not in qbs, not sure), after upgrading 
Creator to 3.2 (just downloaded Win installer).
When build executed, SOMETIMES qbs instantly starting rebuilding one of 
the files. mutexRW.cpp (it tiny wrapper on boost thread and IPC mutexes).
i've tried to rename file, issue gone, but after some time appeared 
again. Using previous version (qtc 3.1.2) - all seems ok.
Then... i tried to create minimal project (with only that file and 
boost) - i have no luck.
Also, it repeats regularry on three dev machines (same qbs version). It 
also repeats on two large projects (tens of products), each of them have 
library with that 'mutexRW.cpp' file. qbs product configuration duplicated.
So... if i modify cpp file, header for it, then SOMETIMES it stops its 
instant-builds :)

I have not tried to build cmd version of current master yet. I think i 
became insane trying to reproduce (it behaves RANDOMLY for me), but I 
plan to  have several tries later. Though, full rebuild helps (time to 
drink coffee?).
I want to use qbs to forget about "full rebuilds"!

Any idea how to debug it, get more info?