Disable libnl by default when building with included libpcap

Libpcap only needs libnl for monitor-mode sniffing. Disabling it lets us
not worry about which -lnl or -lnl-3 linker argument to include in our
own LIBS, so Nmap builds properly no matter whether libnl is present or
not.

configure

@@ -6455,64 +6455,6 @@ if test $have_libpcap != yes; then
 
 $as_echo "#define PCAP_INCLUDED 1" >>confdefs.h
 
-
-  # libpcap can require libnl
-  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for library containing nl_handle_alloc" >&5
-$as_echo_n "checking for library containing nl_handle_alloc... " >&6; }
-if ${ac_cv_search_nl_handle_alloc+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  ac_func_search_save_LIBS=$LIBS
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-
-/* Override any GCC internal prototype to avoid an error.
-   Use char because int might match the return type of a GCC
-   builtin and then its argument prototype would still apply.  */
-#ifdef __cplusplus
-extern "C"
-#endif
-char nl_handle_alloc ();
-int
-main ()
-{
-return nl_handle_alloc ();
-  ;
-  return 0;
-}
-_ACEOF
-for ac_lib in '' nl; do
-  if test -z "$ac_lib"; then
-    ac_res="none required"
-  else
-    ac_res=-l$ac_lib
-    LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
-  fi
-  if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_search_nl_handle_alloc=$ac_res
-fi
-rm -f core conftest.err conftest.$ac_objext \
-    conftest$ac_exeext
-  if ${ac_cv_search_nl_handle_alloc+:} false; then :
-  break
-fi
-done
-if ${ac_cv_search_nl_handle_alloc+:} false; then :
-
-else
-  ac_cv_search_nl_handle_alloc=no
-fi
-rm conftest.$ac_ext
-LIBS=$ac_func_search_save_LIBS
-fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_search_nl_handle_alloc" >&5
-$as_echo "$ac_cv_search_nl_handle_alloc" >&6; }
-ac_res=$ac_cv_search_nl_handle_alloc
-if test "$ac_res" != no; then :
-  test "$ac_res" = "none required" || LIBS="$ac_res $LIBS"
-
-fi
-
 else
   # We assume our included libpcap doesn't need this check-and-define
 

configure.ac

@@ -443,9 +443,6 @@ if test $have_libpcap != yes; then
   PCAP_CLEAN="pcap_clean"
   PCAP_DIST_CLEAN="pcap_dist_clean"
   AC_DEFINE(PCAP_INCLUDED, 1, [Using included libpcap])
-
-  # libpcap can require libnl
-  AC_SEARCH_LIBS(nl_handle_alloc, nl)
 else
   # We assume our included libpcap doesn't need this check-and-define
   PCAP_DEFINE_NETMASK_UNKNOWN

libpcap/NMAP_MODIFICATIONS/0003-Disable-unnecessary-features.patch

@@ -1,7 +1,29 @@
+The following features are disabled:
+
+* monitor-mode sniffing of wireless interfaces on Linux, via libnl
+* building shared libraries
+* Bluetooth support
+* canusb support
+* CAN support
+* dbus capture support
+
 diff --git a/libpcap/configure.in b/libpcap/configure.in
 index 5386062..8ceddd7 100644
 --- a/libpcap/configure.in
 +++ b/libpcap/configure.in
+@@ -441,10 +441,10 @@ linux)
+ 	# Do we have libnl?
+ 	#
+ 	AC_ARG_WITH(libnl,
+-	AC_HELP_STRING([--without-libnl],[disable libnl support @<:@default=yes, on Linux, if present@:>@]),
++	AC_HELP_STRING([--without-libnl],[disable libnl support @<:@default=disabled@:>@]),
+ 		with_libnl=$withval,,)
+ 
+-	if test x$with_libnl != xno ; then
++	if test x$with_libnl = xyes ; then
+ 		have_any_nl="no"
+ 
+ 		#
 @@ -1285,8 +1285,8 @@ solaris*)
  esac
  

libpcap/configure

@@ -1388,8 +1388,7 @@ Optional Packages:
   --without-gcc           don't use gcc
   --with-sita             include SITA support
   --with-pcap=TYPE        use packet capture TYPE
-  --without-libnl         disable libnl support [default=yes, on Linux, if
+  --without-libnl         disable libnl support [default=disabled]
-                          present]
   --with-dag[=DIR]        include Endace DAG support ["yes", "no" or DIR;
                           default="yes" on BSD and Linux if present]
   --with-dag-includes=DIR Endace DAG include directory
@@ -5500,7 +5499,7 @@ if test "${with_libnl+set}" = set; then :
 fi
 
 
-	if test x$with_libnl != xno ; then
+	if test x$with_libnl = xyes ; then
 		have_any_nl="no"
 
 		#

libpcap/configure.in

@@ -441,10 +441,10 @@ linux)
 	# Do we have libnl?
 	#
 	AC_ARG_WITH(libnl,
-	AC_HELP_STRING([--without-libnl],[disable libnl support @<:@default=yes, on Linux, if present@:>@]),
+	AC_HELP_STRING([--without-libnl],[disable libnl support @<:@default=disabled@:>@]),
 		with_libnl=$withval,,)
 
-	if test x$with_libnl != xno ; then
+	if test x$with_libnl = xyes ; then
 		have_any_nl="no"
 
 		#