Move capdns from tcpdump.c to addrtoname.c.

Address the warning below (specific to a few versions of Clang, CMake
and FreeBSD) and update the exemption rule comment in build.sh.

tcpdump.c:244:16: warning: no previous extern declaration for non-static
  variable 'capdns' [-Wmissing-variable-declarations]

4 files changed, 6 insertions, 7 deletions

diff --git a/addrtoname.c b/addrtoname.c
index 58ced4f9..eb3df77e 100644
--- a/addrtoname.c
+++ b/addrtoname.c
@@ -254,7 +254,7 @@ intoa(uint32_t addr)
 static uint32_t f_netmask;
 static uint32_t f_localnet;
 #ifdef HAVE_CASPER
-extern cap_channel_t *capdns;
+cap_channel_t *capdns;
 #endif
 
 /*
diff --git a/addrtoname.h b/addrtoname.h
index 94b41d7b..597f4e1e 100644
--- a/addrtoname.h
+++ b/addrtoname.h
@@ -21,6 +21,11 @@
 
 #include "extract.h"
 
+#ifdef HAVE_CASPER
+#include <libcasper.h>
+extern cap_channel_t *capdns;
+#endif
+
 /*
  * Definition to let us compile most of the IPv6 code even on systems
  * without IPv6 support.
diff --git a/build.sh b/build.sh
index 3588f81c..16a09458 100755
--- a/build.sh
+++ b/build.sh
@@ -42,8 +42,6 @@ FreeBSD-*/yes)
         #   [-Werror,-Wc11-extensions]
         # tcpdump.c:2443:9: error: '_Generic' is a C11 extension
         #   [-Werror,-Wc11-extensions]
-        # tcpdump.c:244:16: error: no previous extern declaration for non-static variable
-        #   'capdns' [-Werror,-Wmissing-variable-declarations]
         TCPDUMP_TAINTED=yes
         ;;
     esac
diff --git a/tcpdump.c b/tcpdump.c
index 1e105eba..dc072e1f 100644
--- a/tcpdump.c
+++ b/tcpdump.c
@@ -240,10 +240,6 @@ static int infoprint;
 
 char *program_name;
 
-#ifdef HAVE_CASPER
-cap_channel_t *capdns;
-#endif
-
 /* Forwards */
 static void (*setsignal (int sig, void (*func)(int)))(int);
 static void cleanup(int);