BSD make support

Makefile

@@ -64,8 +64,10 @@ nettle_libs =   `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_DNSSEC $(PKG_CONFIG
 gmp_libs =      `echo $(COPTS) | $(top)/bld/pkg-wrapper HAVE_DNSSEC NO_GMP --copy -lgmp`
 sunos_libs =    `if uname | grep SunOS >/dev/null 2>&1; then echo -lsocket -lnsl -lposix4; fi`
 version =     -DVERSION='\"`$(top)/bld/get-version $(top)`\"'
-copts_conf = .copts_$(shell $(CC) -DDNSMASQ_COMPILE_OPTS $(COPTS) -E $(top)/$(SRC)/dnsmasq.h | \
-			( md5sum 2>/dev/null || md5 ) | cut -f 1 -d ' ')
+
+sum?=$(shell $(CC) -DDNSMASQ_COMPILE_OPTS $(COPTS) -E $(top)/$(SRC)/dnsmasq.h | ( md5sum 2>/dev/null || md5 ) | cut -f 1 -d ' ')
+sum!=$(CC) -DDNSMASQ_COMPILE_OPTS $(COPTS) -E $(top)/$(SRC)/dnsmasq.h | ( md5sum 2>/dev/null || md5 ) | cut -f 1 -d ' '
+copts_conf = .copts_$(sum)
 
 objs = cache.o rfc1035.o util.o option.o forward.o network.o \
        dnsmasq.o dhcp.o lease.o rfc2131.o netlink.o dbus.o bpf.o \