Turn some compiler warnings into errors

Re-apply the reverted commit 98bc7fa50d0731864297f8fb82932d480c426ff6, this
time with a clear error message in case autoconf-archive is not installed.

Change-Id: I631bde22e79ec0318eb9c8114db5861a1d635816
Tweaked-by: Neels Hofmeyr <nhofmeyr@sysmocom.de>
diff --git a/debian/control b/debian/control
index 44262b9..93b4bd3 100644
--- a/debian/control
+++ b/debian/control
@@ -4,6 +4,7 @@
 Priority: optional
 Build-Depends: debhelper (>= 9),
                autotools-dev,
+               autoconf-archive,
                pkg-config,
                libgtp0-dev,
                libosmocore-dev,