pkg/60077: pkgsrc build process gets stuck on Linux does to empty variable

>Number:         60077
>Category:       pkg
>Synopsis:       pkgsrc build process gets stuck on Linux does to empty variable
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Mar 13 05:40:00 +0000 2026
>Originator:     Antal
>Release:        pkgsrc 2026-march-12
>Organization:
>Environment:
Linux debian 6.19.6+deb14-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.19.6-1 (2026-03-06) x86_64 GNU/Linux
(Debian sid)
>Description:
* bootstrapped system, installed into /opt/pkg
* PATH contains /opt/pkg/bin
* issued bmake in: /usr/src/pkgsrc/www/dillo
* process got stuck here: 
===> Checking for vulnerabilities in bsdtar-3.8.5
===> Building for bsdtar-3.8.5
/usr/src/pkgsrc/archivers/bsdtar/work/.tools/bin/mkdir -p libarchive/test
grep -h '^DEFINE_TEST('  | LC_COLLATE=C sort > libarchive/test/list.h

===================================
grep does not seem to have input to search in.

>How-To-Repeat:

>Fix: