Fix gyp's relative path calculation

Gyp could not calculate the relative path between an two absolute paths
with drive letters. Getting rid of the drive letters solves the issue.

Make sure to compare directories in lower-case as Windows is case-
insensitive, and we otherwise get very long paths that confuses ninja.

We do preserve case in the path names, which is needed for some parts
of the build system.

Change-Id: I4b4a45155b258ae7fe207c961571d27a41949b85
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>
Reviewed-by: Michael Brüning <michael.bruning@qt.io>

0 files changed, 0 insertions, 0 deletions