dpkg-checkbuilddeps: Exit with 1 on unsatisfied dependencies

Regression introduced in commit d287060bb1a45f5de33eb27034a7d8b27b039dbb.

We cannot rely on die's error code as it might be anything.

Prompted-by: David Kalnischkies <david@kalnischkies.de>

debian/changelog

@@ -17,6 +17,8 @@ dpkg (1.18.4) UNRELEASED; urgency=low
     agnostic.
   * Add ‘.gitreview’ to the default dpkg-source ignore lists.
   * Add support for DPKG_MAINTSCRIPT_DEBUG environment variable to dpkg.
+  * Fix dpkg-checkbuilddeps exit code to be 1 instead of a random error value
+    on unsatisfied dependencies. Regression introduced in dpkg 1.18.3.
   * Test suite:
     - Improve perl code test coverage.
   * Build system:

scripts/dpkg-checkbuilddeps.pl

@@ -138,12 +138,12 @@ if ($bc_value) {
 }
 
 if (@unmet) {
-	error(g_('Unmet build dependencies: %s'),
-	      join(' ', map { $_->output() } @unmet));
+	errormsg(g_('Unmet build dependencies: %s'),
+	         join(' ', map { $_->output() } @unmet));
 }
 if (@conflicts) {
-	error(g_('Build conflicts: %s'),
-	      join(' ', map { $_->output() } @conflicts));
+	errormsg(g_('Build conflicts: %s'),
+	         join(' ', map { $_->output() } @conflicts));
 }
 exit 1 if @unmet || @conflicts;