The linemarkers in the preprocessor output from gcc5 on Cygwin have
canonicalized paths to included files (e.g. xserver/build/../include/misc.h
is canonicalized to xserver/build/include/misc.h). (see gcc svn rev 210264,
which causes the transformation performed by -fcanonical-system-headers to
be applied to all include pathnames)
These canonicalized paths won't match $topdir, so sdksyms doesn't look at
the contents of those headers for sdk exported symbols.
Workaround this by canonicalizing all the paths we consider, using readlink.
v2:
Keep a cache of readlink results so it isn't quite so dreadfully slow.
Reviewed-by: Adam Jackson <ajax@redhat.com>
bca2216090