dhcp cross compile support integration

Allow BINDCONFIG to be initialized in environment passed to configure.

Allow archiver to be determined during configure.

This patch is submitted upstream as part of a cross compiling enhancement
suggestion to dhcp-suggest@isc.org. Reference ISC-Bugs #41502.

Signed-off-by: Doug Kehn <rdkehn@yahoo.com>

Index: dhcp-4.3.3-P1/configure.ac
===================================================================
--- dhcp-4.3.3-P1.orig/configure.ac
+++ dhcp-4.3.3-P1/configure.ac
@@ -33,7 +33,7 @@ if test "$GCC" = "yes"; then
 fi
 
 # We can have some flags to pass to bind configure
-BINDCONFIG=
+BINDCONFIG="$BINDCONFIG"
 AC_SUBST(BINDCONFIG)
 
 # POSIX doesn't include the IPv6 Advanced Socket API and glibc hides
@@ -43,6 +43,9 @@ AC_SUBST(BINDCONFIG)
 # Use this to define _GNU_SOURCE to pull in the IPv6 Advanced Socket API.
 AC_USE_SYSTEM_EXTENSIONS
 
+AC_CHECK_TOOL(AR,ar)
+AC_SUBST(AR)
+
 AC_PROG_RANLIB
 AC_CONFIG_HEADERS([includes/config.h])