configure: make source tree build more robust
When source directory can be arrived at by two paths,
configure might misdetect an out of tree build.
The simplest way to trigger the problem is running
configure using a full path. E.g. (<firstpath> refers to qemu source
tree):
ln -s <firstpath> <secondpath>
cd <firstpath>
<secondpath>/configure
A more practical way is when make runs configure automatically:
1. cd <firstpath>/; ./configure
SRC_PATH=<firstpath>/ is written into config_host.mak
2. cd <secondpath>/; touch configure; make
make now runs <firstpath>/configure, so configure
assumes it's an out of tree build
When this happens configure overwrites parts of
the current tree with symlinks.
Make the test more robust: create a canary file under
the build tree, then look for it in the source tree.
If there - we know it's a source build!
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
1 file changed
