Linux build: Use sysroot when calculating dependencies

third_party/dpkg-dev/scripts/Dpkg/File.pm

+# Copyright © 2011 Raphaël Hertzog <hertzog@debian.org>
+# Copyright © 2012 Guillem Jover <guillem@debian.org>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package Dpkg::File;
+
+use strict;
+use warnings;
+
+our $VERSION = '0.01';
+
+use Fcntl qw(:flock);
+use Dpkg::Gettext;
+use Dpkg::ErrorHandling;
+
+use Exporter qw(import);
+our @EXPORT = qw(file_lock file_slurp);
+
+sub file_lock($$) {
+    my ($fh, $filename) = @_;
+
+    # A strict dependency on libfile-fcntllock-perl being it an XS module,
+    # and dpkg-dev indirectly making use of it, makes building new perl
+    # package which bump the perl ABI impossible as these packages cannot
+    # be installed alongside.
+    eval 'use File::FcntlLock';
+    if ($@) {
+        warning(_g('File::FcntlLock not available; using flock which is not NFS-safe'));
+        flock($fh, LOCK_EX)
+            or syserr(_g('failed to get a write lock on %s'), $filename);
+    } else {
+        eval q{
+            my $fs = File::FcntlLock->new(l_type => F_WRLCK);
+            $fs->lock($fh, F_SETLKW)
+                or syserr(_g('failed to get a write lock on %s'), $filename);
+        }
+    }
+}
+
+sub file_slurp {
+    my ($fh) = @_;
+
+    local $/;
+    my $data = <$fh>;
+    return $data;
+}
+
+1;