Bug#724907: lintian: [new check] warn on deprecated find -perm +x option

[Andreas Metzler <ametzler@bebt.de>]

Package: lintian
Version: 2.5.19
Severity: wishlist

Hello,

GNU find 4.5.11 and later do not support the -perm +x option anymore
(due to being "unspecified behavior" in POSIX).

It would be nice to search for invalid find-invocations before a find
version with this feature ends up in unstable.

What is needed is essentially

Tag: findpermplus
Severity: important
Certainty: wild-guess
Info: The package probably invokes find with the -perm +X option. This
 option is deprecated and not supported in 4.5.11 and later. Please use
 -perm /X instead.

Where findpermplus does a 
find -path debian/changelog -or \( -type f -exec grep -l -- '-perm +' {} + \)

i.e. a grep for a literal '-perm +'. The check should not only look
at debian but the complete source.

An enhanced check would additionally match on 'find.*-perm +' with
Certainty: possible.

Thanks for considering,
cu Andreas