cleanup headers and especially #includes everywhere

Beside being a bit cleaner it hopefully also resolves oddball problems
I have with high levels of parallel jobs.

Git-Dch: Ignore
Reported-By: iwyu (include-what-you-use)

1 files changed, 4 insertions, 1 deletions

diff --git a/apt-pkg/policy.h b/apt-pkg/policy.h
index 5172a3c3b..f15d8c0a0 100644
--- a/apt-pkg/policy.h
+++ b/apt-pkg/policy.h
@@ -33,10 +33,13 @@
 #ifndef PKGLIB_POLICY_H
 #define PKGLIB_POLICY_H
 
-
 #include <apt-pkg/depcache.h>
+#include <apt-pkg/pkgcache.h>
+#include <apt-pkg/cacheiterators.h>
 #include <apt-pkg/versionmatch.h>
+
 #include <vector>
+#include <string>
 
 #ifndef APT_8_CLEANER_HEADERS
 using std::vector;