dpkg-deb: Use DEBMAGIC instead of string literals

dpkg-deb/build.c

@@ -448,7 +448,7 @@ void do_build(const char *const *argv) {
     thetime = time(NULL);
     if (fprintf(ar,
                 "!<arch>\n"
-                "debian-binary   %-12lu0     0     100644  %-10ld`\n"
+                DEBMAGIC "%-12lu0     0     100644  %-10ld`\n"
                 ARCHIVEVERSION "\n"
                 "%s"
                 ADMINMEMBER "%-12lu0     0     100644  %-10ld`\n",

dpkg-deb/extract.c

@@ -142,7 +142,7 @@ void extracthalf(const char *debar, const char *directory,
       memberlen= parseheaderlength(arh.ar_size,sizeof(arh.ar_size),
                                    debar, _("member length"));
       if (!header_done) {
-        if (memcmp(arh.ar_name,"debian-binary   ",sizeof(arh.ar_name)) &&
+        if (memcmp(arh.ar_name, DEBMAGIC, sizeof(arh.ar_name)) &&
 	    memcmp(arh.ar_name,"debian-binary/   ",sizeof(arh.ar_name)))
           ohshit(_("file `%.250s' is not a debian binary archive (try dpkg-split?)"),debar);
         infobuf= m_malloc(memberlen+1);