package/dhcp: fix build without atomic

Fix the following build failure without atomic raised since commit
fde21979427ffeb4fe9c0068310be195f2dec5ec:

/nvmedata/autobuild/instance-25/output-1/host/lib/gcc/mipsel-buildroot-linux-uclibc/10.3.0/../../../../mipsel-buildroot-linux-uclibc/bin/ld: cannot find -latomic: No such file or directory

Fixes:
 - http://autobuild.buildroot.org/results/db6/db6923915e36bcdb2953a3cdd2b450fa10794631

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/dhcp/dhcp.mk

@@ -62,9 +62,14 @@ else
 DHCP_BIND_EXTRA_CONFIG += --without-zlib
 endif
 
+ifeq ($(BR2_TOOLCHAIN_HAS_ATOMIC),y)
+DHCP_BIND_EXTRA_CONFIG += --enable-atomic
 ifeq ($(BR2_TOOLCHAIN_HAS_LIBATOMIC),y)
 DHCP_CONF_ENV += LIBS=-latomic
 endif
+else
+DHCP_BIND_EXTRA_CONFIG += --disable-atomic
+endif
 
 ifeq ($(BR2_STATIC_LIBS),y)
 DHCP_CONF_OPTS += --disable-libtool