configure: check for gethostbyaddr(), not gethostbyname().

We use gethostbyaddr() to translate IP addresses in packets to names; we
don't use gethostbyname() to translate names to IP addresses (libpcap
does the latter when compiling filters, so we leave that up to it, and
nothing's left for us to do).

This probably has the same effect as checking for gethostbyname(), but
it makes it a bit clearer why we'd check for it.

(cherry picked from commit b1ccc20)

Author: guyharris

aclocal.m4

@@ -1045,11 +1045,11 @@ dnl
 dnl AC_LBL_LIBRARY_NET
 dnl
 dnl This test is for network applications that need socket() and
-dnl gethostbyname() -ish functions.  Under Solaris, those applications
+dnl gethostbyaddr() -ish functions.  Under Solaris, those applications
 dnl need to link with "-lsocket -lnsl".  Under IRIX, they need to link
 dnl with "-lnsl" but should *not* link with "-lsocket" because
 dnl libsocket.a breaks a number of things (for instance:
-dnl gethostbyname() under IRIX 5.2, and snoop sockets under most
+dnl gethostbyaddr() under IRIX 5.2, and snoop sockets under most
 dnl versions of IRIX).
 dnl
 dnl Unfortunately, many application developers are not aware of this,
@@ -1077,16 +1077,16 @@ dnl statically and happen to have a libresolv.a lying around (and no
 dnl libnsl.a).
 dnl
 AC_DEFUN(AC_LBL_LIBRARY_NET, [
-    # Most operating systems have gethostbyname() in the default searched
+    # Most operating systems have gethostbyaddr() in the default searched
     # libraries (i.e. libc):
     # Some OSes (eg. Solaris) place it in libnsl
     # Some strange OSes (SINIX) have it in libsocket:
-    AC_SEARCH_LIBS(gethostbyname, nsl socket resolv)
+    AC_SEARCH_LIBS(gethostbyaddr, nsl socket resolv)
     # Unfortunately libsocket sometimes depends on libnsl and
     # AC_SEARCH_LIBS isn't up to the task of handling dependencies like this.
-    if test "$ac_cv_search_gethostbyname" = "no"
+    if test "$ac_cv_search_gethostbyaddr" = "no"
     then
-	AC_CHECK_LIB(socket, gethostbyname,
+	AC_CHECK_LIB(socket, gethostbyaddr,
                      LIBS="-lsocket -lnsl $LIBS", , -lnsl)
     fi
     AC_SEARCH_LIBS(socket, socket, ,