libtool: The new xattr dependency makes many packages no longer binary distributable

[yan12125 (Chih-Hsuan Yen)]

Since ​https://github.com/macports/macports-ports/commit/ac7eb8e931c616bdddcdb5733c86fb9067619d45, many packages are no longer binary distributable. For example, in a recent cmake build [1]:

"cmake" is not distributable because its dependency "xattr" has license "unknown" which is not known to be distributable

I guess the dependency graph is: cmake -> curl -> libidn2 -> libtool -> xattr. (Any systematic way to track down the actual breakage?)

As xattr is only used to strip extended attributes, I suggest to add it to license_noconflict:

diff --git a/devel/libtool/Portfile b/devel/libtool/Portfile
index ddf67d94a1..bf2f7bb234 100644
--- a/devel/libtool/Portfile
+++ b/devel/libtool/Portfile
@@ -25,6 +25,7 @@ checksums           rmd160  6f4b4c3e89426652da3acffa707f71bb4ccee26a \

 # To clean up libtool 2.4.6 distfile.
 depends_build       bin:xattr:xattr
+license_noconflict  xattr

 patchfiles          hardcode-m4.patch asan.patch
 post-patch {

With that cmake is binary distributable again.

CC'ing the maintainer and the author of the relevant commit.

[1] ​https://build.macports.org/builders/ports-10.13_x86_64-builder/builds/11688/steps/gather-archives/logs/stdio