Enable -Wredundant-decls.

Add it to the default list of checks, and fix some errors it causes.
(Sadly, it doesn't work in CLang.)

18 files changed, 155 insertions, 87 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index f6e807af9e..26ff0aa36d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -582,6 +582,7 @@ else() # ! MSVC
 		-Wheader-guard
 		-Wcomma
 		-Wshorten-64-to-32
+		-Wredundant-decls
 	)
 
 	#
@@ -675,12 +676,6 @@ else() # ! MSVC
 			#
 			-Wcast-qual
 			#
-			# Some generated ASN.1 dissectors block this one;
-			# multiple function declarations for the same
-			# function are being generated.
-			#
-			-Wredundant-decls
-			#
 			# All the registration functions block these for now.
 			#
 			-Wmissing-prototypes
diff --git a/capinfos.c b/capinfos.c
index 05110e3880..ddc224d2e9 100644
--- a/capinfos.c
+++ b/capinfos.c
@@ -51,8 +51,17 @@
 #include <locale.h>
 #include <errno.h>
 
-#ifdef HAVE_GETOPT_H
+/*
+ * If we have getopt_long() in the system library, include <getopt.h>.
+ * Otherwise, we're using our own getopt_long() (either because the
+ * system has getopt() but not getopt_long(), as with some UN*Xes,
+ * or because it doesn't even have getopt(), as with Windows), so
+ * include our getopt_long()'s header.
+ */
+#ifdef HAVE_GETOPT_LONG
 #include <getopt.h>
+#else
+#include <wsutil/wsgetopt.h>
 #endif
 
 #include <glib.h>
@@ -76,10 +85,6 @@
 
 #include <wsutil/wsgcrypt.h>
 
-#ifndef HAVE_GETOPT_LONG
-#include "wsutil/wsgetopt.h"
-#endif
-
 #include "ui/failure_message.h"
 
 #define INVALID_OPTION 1
diff --git a/captype.c b/captype.c
index e3ee9c929f..0a620af0c4 100644
--- a/captype.c
+++ b/captype.c
@@ -20,8 +20,17 @@
 #include <locale.h>
 #include <errno.h>
 
-#ifdef HAVE_GETOPT_H
+/*
+ * If we have getopt_long() in the system library, include <getopt.h>.
+ * Otherwise, we're using our own getopt_long() (either because the
+ * system has getopt() but not getopt_long(), as with some UN*Xes,
+ * or because it doesn't even have getopt(), as with Windows), so
+ * include our getopt_long()'s header.
+ */
+#ifdef HAVE_GETOPT_LONG
 #include <getopt.h>
+#else
+#include <wsutil/wsgetopt.h>
 #endif
 
 #include <glib.h>
@@ -42,10 +51,6 @@
 #include <wsutil/report_message.h>
 #include <wsutil/str_util.h>
 
-#ifndef HAVE_GETOPT_LONG
-#include "wsutil/wsgetopt.h"
-#endif
-
 #include "ui/failure_message.h"
 
 static void
diff --git a/dumpcap.c b/dumpcap.c
index 24c8a610ab..8a64a20510 100644
--- a/dumpcap.c
+++ b/dumpcap.c
@@ -21,8 +21,17 @@
 #include <netinet/in.h>
 #endif
 
-#ifdef HAVE_GETOPT_H
+/*
+ * If we have getopt_long() in the system library, include <getopt.h>.
+ * Otherwise, we're using our own getopt_long() (either because the
+ * system has getopt() but not getopt_long(), as with some UN*Xes,
+ * or because it doesn't even have getopt(), as with Windows), so
+ * include our getopt_long()'s header.
+ */
+#ifdef HAVE_GETOPT_LONG
 #include <getopt.h>
+#else
+#include <wsutil/wsgetopt.h>
 #endif
 
 #if defined(__APPLE__) && defined(__LP64__)
@@ -39,10 +48,6 @@
 
 #include <wsutil/socket.h>
 
-#ifndef HAVE_GETOPT_LONG
-#include "wsutil/wsgetopt.h"
-#endif
-
 #ifdef HAVE_LIBCAP
 # include <sys/prctl.h>
 # include <sys/capability.h>
diff --git a/editcap.c b/editcap.c
index 3751aad84a..cc90d33a2a 100644
--- a/editcap.c
+++ b/editcap.c
@@ -40,8 +40,17 @@
 #include <unistd.h>
 #endif
 
-#ifdef HAVE_GETOPT_H
+/*
+ * If we have getopt_long() in the system library, include <getopt.h>.
+ * Otherwise, we're using our own getopt_long() (either because the
+ * system has getopt() but not getopt_long(), as with some UN*Xes,
+ * or because it doesn't even have getopt(), as with Windows), so
+ * include our getopt_long()'s header.
+ */
+#ifdef HAVE_GETOPT_LONG
 #include <getopt.h>
+#else
+#include <wsutil/wsgetopt.h>
 #endif
 
 #include <wiretap/secrets-types.h>
@@ -50,10 +59,6 @@
 #include "epan/etypes.h"
 #include "epan/dissectors/packet-ieee80211-radiotap-defs.h"
 
-#ifndef HAVE_GETOPT_LONG
-#include "wsutil/wsgetopt.h"
-#endif
-
 #ifdef _WIN32
 #include <process.h>    /* getpid */
 #include <winsock2.h>
diff --git a/extcap/extcap-base.c b/extcap/extcap-base.c
index 68c15ae57d..bc09aa6c54 100644
--- a/extcap/extcap-base.c
+++ b/extcap/extcap-base.c
@@ -19,13 +19,19 @@
 #include <string.h>
 #include <errno.h>
 
-#ifdef HAVE_GETOPT_H
-    #include <getopt.h>
+/*
+ * If we have getopt_long() in the system library, include <getopt.h>.
+ * Otherwise, we're using our own getopt_long() (either because the
+ * system has getopt() but not getopt_long(), as with some UN*Xes,
+ * or because it doesn't even have getopt(), as with Windows), so
+ * include our getopt_long()'s header.
+ */
+#ifdef HAVE_GETOPT_LONG
+#include <getopt.h>
+#else
+#include <wsutil/wsgetopt.h>
 #endif
 
-#ifndef HAVE_GETOPT_LONG
-    #include "wsutil/wsgetopt.h"
-#endif
 #include "ws_attributes.h"
 
 enum extcap_options {
diff --git a/extcap/extcap-base.h b/extcap/extcap-base.h
index 11c4431093..20d4be31c3 100644
--- a/extcap/extcap-base.h
+++ b/extcap/extcap-base.h
@@ -19,12 +19,17 @@
 #include <stdlib.h>
 #include <stdint.h>
 
-#ifdef HAVE_GETOPT_H
+/*
+ * If we have getopt_long() in the system library, include <getopt.h>.
+ * Otherwise, we're using our own getopt_long() (either because the
+ * system has getopt() but not getopt_long(), as with some UN*Xes,
+ * or because it doesn't even have getopt(), as with Windows), so
+ * include our getopt_long()'s header.
+ */
+#ifdef HAVE_GETOPT_LONG
 	#include <getopt.h>
-#endif
-
-#ifndef HAVE_GETOPT_LONG
-	#include "wsutil/wsgetopt.h"
+#else
+	#include <wsutil/wsgetopt.h>
 #endif
 
 #ifdef _WIN32
diff --git a/mergecap.c b/mergecap.c
index f9a6c417eb..96856b533f 100644
--- a/mergecap.c
+++ b/mergecap.c
@@ -18,18 +18,23 @@
 #include <errno.h>
 #include <glib.h>
 
-#ifdef HAVE_GETOPT_H
+/*
+ * If we have getopt_long() in the system library, include <getopt.h>.
+ * Otherwise, we're using our own getopt_long() (either because the
+ * system has getopt() but not getopt_long(), as with some UN*Xes,
+ * or because it doesn't even have getopt(), as with Windows), so
+ * include our getopt_long()'s header.
+ */
+#ifdef HAVE_GETOPT_LONG
 #include <getopt.h>
+#else
+#include <wsutil/wsgetopt.h>
 #endif
 
 #include <string.h>
 
 #include <wiretap/wtap.h>
 
-#ifndef HAVE_GETOPT_LONG
-#include <wsutil/wsgetopt.h>
-#endif
-
 #include <ui/clopts_common.h>
 #include <ui/cmdarg_err.h>
 #include <wsutil/filesystem.h>
diff --git a/plugins/epan/profinet/packet-pn-rsi.c b/plugins/epan/profinet/packet-pn-rsi.c
index 297278cc81..ef6e5fd0b5 100644
--- a/plugins/epan/profinet/packet-pn-rsi.c
+++ b/plugins/epan/profinet/packet-pn-rsi.c
@@ -229,9 +229,6 @@ static const range_string pn_rsi_interface[] = {
     { 0, NULL }
 };*/
 
-int dissect_blocks(tvbuff_t *tvb, int offset,
-    packet_info *pinfo, proto_tree *tree, guint8 *drep);
-
 static int
 dissect_FOpnumOffset(tvbuff_t *tvb, int offset,
     packet_info *pinfo _U_, proto_tree *tree, guint8 *drep _U_, guint32 *u32FOpnumOffset)
diff --git a/randpkt.c b/randpkt.c
index d97ef04e39..e4c05fe14a 100644
--- a/randpkt.c
+++ b/randpkt.c
@@ -27,12 +27,18 @@
 #endif
 
 #include <wsutil/report_message.h>
-#ifdef HAVE_GETOPT_H
-#include <getopt.h>
-#endif
 
-#ifndef HAVE_GETOPT_LONG
-#include "wsutil/wsgetopt.h"
+/*
+ * If we have getopt_long() in the system library, include <getopt.h>.
+ * Otherwise, we're using our own getopt_long() (either because the
+ * system has getopt() but not getopt_long(), as with some UN*Xes,
+ * or because it doesn't even have getopt(), as with Windows), so
+ * include our getopt_long()'s header.
+ */
+#ifdef HAVE_GETOPT_LONG
+#include <getopt.h>
+#else
+#include <wsutil/wsgetopt.h>
 #endif
 
 #include "randpkt_core/randpkt_core.h"
diff --git a/rawshark.c b/rawshark.c
index 4f6585603d..aa822ab07f 100644
--- a/rawshark.c
+++ b/rawshark.c
@@ -33,14 +33,19 @@
 #include <sys/resource.h>
 #endif
 
-#ifdef HAVE_GETOPT_H
-#include <getopt.h>
-#endif
-
 #include <errno.h>
 
-#ifndef HAVE_GETOPT_LONG
-#include "wsutil/wsgetopt.h"
+/*
+ * If we have getopt_long() in the system library, include <getopt.h>.
+ * Otherwise, we're using our own getopt_long() (either because the
+ * system has getopt() but not getopt_long(), as with some UN*Xes,
+ * or because it doesn't even have getopt(), as with Windows), so
+ * include our getopt_long()'s header.
+ */
+#ifdef HAVE_GETOPT_LONG
+#include <getopt.h>
+#else
+#include <wsutil/wsgetopt.h>
 #endif
 
 #include <glib.h>
diff --git a/reordercap.c b/reordercap.c
index 3d225bdec0..17408a848b 100644
--- a/reordercap.c
+++ b/reordercap.c
@@ -15,16 +15,21 @@
 #include <string.h>
 #include <glib.h>
 
-#ifdef HAVE_GETOPT_H
+/*
+ * If we have getopt_long() in the system library, include <getopt.h>.
+ * Otherwise, we're using our own getopt_long() (either because the
+ * system has getopt() but not getopt_long(), as with some UN*Xes,
+ * or because it doesn't even have getopt(), as with Windows), so
+ * include our getopt_long()'s header.
+ */
+#ifdef HAVE_GETOPT_LONG
 #include <getopt.h>
+#else
+#include <wsutil/wsgetopt.h>
 #endif
 
 #include <wiretap/wtap.h>
 
-#ifndef HAVE_GETOPT_LONG
-#include "wsutil/wsgetopt.h"
-#endif
-
 #include <ui/cmdarg_err.h>
 #include <wsutil/filesystem.h>
 #include <wsutil/file_util.h>
diff --git a/text2pcap.c b/text2pcap.c
index 8e3a1b7273..9cdee935de 100644
--- a/text2pcap.c
+++ b/text2pcap.c
@@ -112,17 +112,22 @@
 #include <time.h>
 #include <glib.h>
 
-#ifdef HAVE_GETOPT_H
+/*
+ * If we have getopt_long() in the system library, include <getopt.h>.
+ * Otherwise, we're using our own getopt_long() (either because the
+ * system has getopt() but not getopt_long(), as with some UN*Xes,
+ * or because it doesn't even have getopt(), as with Windows), so
+ * include our getopt_long()'s header.
+ */
+#ifdef HAVE_GETOPT_LONG
 #include <getopt.h>
+#else
+#include <wsutil/wsgetopt.h>
 #endif
 
 #include <errno.h>
 #include <assert.h>
 
-#ifndef HAVE_GETOPT_LONG
-#include "wsutil/wsgetopt.h"
-#endif
-
 #ifndef HAVE_STRPTIME
 # include "wsutil/strptime.h"
 #endif
diff --git a/tfshark.c b/tfshark.c
index b3b3f22fa0..89961f093f 100644
--- a/tfshark.c
+++ b/tfshark.c
@@ -17,16 +17,21 @@
 #include <locale.h>
 #include <limits.h>
 
-#ifdef HAVE_GETOPT_H
+/*
+ * If we have getopt_long() in the system library, include <getopt.h>.
+ * Otherwise, we're using our own getopt_long() (either because the
+ * system has getopt() but not getopt_long(), as with some UN*Xes,
+ * or because it doesn't even have getopt(), as with Windows), so
+ * include our getopt_long()'s header.
+ */
+#ifdef HAVE_GETOPT_LONG
 #include <getopt.h>
+#else
+#include <wsutil/wsgetopt.h>
 #endif
 
 #include <errno.h>
 
-#ifndef HAVE_GETOPT_LONG
-#include "wsutil/wsgetopt.h"
-#endif
-
 #include <glib.h>
 
 #include <epan/exceptions.h>
diff --git a/tools/lemon/lemon.c b/tools/lemon/lemon.c
index 387d094b7f..8f990824a9 100644
--- a/tools/lemon/lemon.c
+++ b/tools/lemon/lemon.c
@@ -48,7 +48,7 @@ extern int access(const char *path, int mode);
 #define MAXRHS 1000
 #endif
 
-extern void memory_error();
+extern void memory_error(void);
 static int showPrecedenceConflict = 0;
 static char *msort(char*,char**,int(*)(const char*,const char*));
 
@@ -430,7 +430,6 @@ struct lemon {
 };
 
 #define MemoryCheck(X) if((X)==0){ \
-  extern void memory_error(); \
   memory_error(); \
 }
 
diff --git a/tshark.c b/tshark.c
index e1247c1537..0239c04f9b 100644
--- a/tshark.c
+++ b/tshark.c
@@ -18,8 +18,17 @@
 #include <locale.h>
 #include <limits.h>
 
-#ifdef HAVE_GETOPT_H
+/*
+ * If we have getopt_long() in the system library, include <getopt.h>.
+ * Otherwise, we're using our own getopt_long() (either because the
+ * system has getopt() but not getopt_long(), as with some UN*Xes,
+ * or because it doesn't even have getopt(), as with Windows), so
+ * include our getopt_long()'s header.
+ */
+#ifdef HAVE_GETOPT_LONG
 #include <getopt.h>
+#else
+#include <wsutil/wsgetopt.h>
 #endif
 
 #include <errno.h>
@@ -32,10 +41,6 @@
 #include <signal.h>
 #endif
 
-#ifndef HAVE_GETOPT_LONG
-#include "wsutil/wsgetopt.h"
-#endif
-
 #include <glib.h>
 
 #include <epan/exceptions.h>
diff --git a/ui/commandline.c b/ui/commandline.c
index e14daa58b9..3dd4c5dd87 100644
--- a/ui/commandline.c
+++ b/ui/commandline.c
@@ -16,12 +16,17 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-#ifdef HAVE_GETOPT_H
+/*
+ * If we have getopt_long() in the system library, include <getopt.h>.
+ * Otherwise, we're using our own getopt_long() (either because the
+ * system has getopt() but not getopt_long(), as with some UN*Xes,
+ * or because it doesn't even have getopt(), as with Windows), so
+ * include our getopt_long()'s header.
+ */
+#ifdef HAVE_GETOPT_LONG
 #include <getopt.h>
-#endif
-
-#ifndef HAVE_GETOPT_LONG
-#include "wsutil/wsgetopt.h"
+#else
+#include <wsutil/wsgetopt.h>
 #endif
 
 #include <version_info.h>
diff --git a/ui/qt/main.cpp b/ui/qt/main.cpp
index 6032054e55..705681e10b 100644
--- a/ui/qt/main.cpp
+++ b/ui/qt/main.cpp
@@ -21,12 +21,17 @@
 #include "ui/win32/console_win32.h"
 #endif
 
-#ifdef HAVE_GETOPT_H
+/*
+ * If we have getopt_long() in the system library, include <getopt.h>.
+ * Otherwise, we're using our own getopt_long() (either because the
+ * system has getopt() but not getopt_long(), as with some UN*Xes,
+ * or because it doesn't even have getopt(), as with Windows), so
+ * include our getopt_long()'s header.
+ */
+#ifdef HAVE_GETOPT_LONG
 #include <getopt.h>
-#endif
-
-#ifndef HAVE_GETOPT_LONG
-#include "wsutil/wsgetopt.h"
+#else
+#include <wsutil/wsgetopt.h>
 #endif
 
 #include <ui/clopts_common.h>