Improve correctstatus speed

Use "apt-cache show" instead of "dumpavail" in the Makefile.

Using "dumpavail" dumps all packages, while we're only interested in one
specific package. This wasts a log of cycles and time when many packages
need fixing.

Use "show $pkg" to directly dump only the requested package.

Use "--no-all-versions" to show only the candidate for installation.

Closes: #759343. Thanks to Philipp Hahn for the patch.

Makefile

@@ -292,9 +292,8 @@ correctstatus: status apt-update
 			export ARCH=$$ARCH; \
 			for i in `$(apt) selected -f install`; do \
 				echo $$ARCH:$$i; \
-				$(apt) cache dumpavail | perl -000 -ne \
-				"s/^(Package: .*)\$$/\$$1\nStatus: install ok installed/m; \
-				print if /^Package: \Q$$i\E\s*\$$/m;" \
+				$(apt) cache --no-all-versions show "$$i" | perl -000 -npe \
+				"s/^(Package: .*)\$$/\$$1\nStatus: install ok installed/m;" \
 				>> $(ADIR)/$(CODENAME)-$$ARCH/status; \
 			done; \
 		done; \

debian/changelog

@@ -4,8 +4,10 @@ debian-cd (3.1.16) UNRELEASED; urgency=medium
   * Fix changelog date for 3.1.15. Closes: #751814
   * Fix up Gnome CD set installing xfce - logic in boot menu creation was
     broken. Closes: #756774
-  * Fix word-splitting regexp in generate_di_list. Closes: #758512. Thanks
-    to Philipp Hahn for the patch.
+
+  [ Philipp Hahn ]
+  * Fix word-splitting regexp in generate_di_list. Closes: #758512.
+  * Improve correctstatus speed. Closes: #759343
 
  -- Steve McIntyre <93sam@debian.org>  Thu, 07 Aug 2014 01:45:01 +0100