color: add win32 support for non-black background
This complicates the code a bit, since attributes need to be masked together
correctly before they are applied. Perhaps the code should be redesigned at
some point, but this works well for now.
#!/bin/sh
hg init test
cd test
echo foo > a
hg ci -Ama
hg up -r0000
echo bar > a
echo % should issue warning
hg ci -Amb
hg up -r0000
echo stuffy > a
echo % should not issue warning
hg ci -q -Amc
hg up -r0000
echo crap > a
hg branch testing
echo % should not issue warning
hg ci -q -Amd