build: allow for applets to be customized

Makefile

@@ -47,11 +47,21 @@ MULTICALL_SRC = \
 MULTICALL_OBJ = ${MULTICALL_SRC:.c=.o}
 MULTICALL = ifupdown
 
+CONFIG_IFQUERY ?= Y
 IFQUERY_SRC = cmd/ifquery.c
-IFQUERY_OBJ = ${IFQUERY_SRC:.c=.o}
+MULTICALL_${CONFIG_IFQUERY}_OBJ += ${IFQUERY_SRC:.c=.o}
+CMDS_${CONFIG_IFQUERY} += ifquery
+CPPFLAGS_${CONFIG_IFQUERY} += -DCONFIG_IFQUERY
 
+CONFIG_IFUPDOWN ?= Y
 IFUPDOWN_SRC = cmd/ifupdown.c
-IFUPDOWN_OBJ = ${IFUPDOWN_SRC:.c=.o}
+MULTICALL_${CONFIG_IFUPDOWN}_OBJ += ${IFUPDOWN_SRC:.c=.o}
+CMDS_${CONFIG_IFUPDOWN} += ifup ifdown
+CPPFLAGS_${CONFIG_IFUPDOWN} += -DCONFIG_IFUPDOWN
+
+MULTICALL_OBJ += ${MULTICALL_Y_OBJ}
+CMDS += ${CMDS_Y}
+CPPFLAGS += ${CPPFLAGS_Y}
 
 EXECUTOR_SCRIPTS_CORE ?= \
 	dhcp \
@@ -68,8 +78,6 @@ EXECUTOR_SCRIPTS_STUB ?=
 
 CMD_OBJ = ${MULTICALL_OBJ} ${IFQUERY_OBJ} ${IFUPDOWN_OBJ}
 
-CMDS = ifup ifdown ifquery
-
 TARGET_LIBS = ${LIBIFUPDOWN_LIB}
 LIBS += ${TARGET_LIBS} ${LIBBSD_LIBS}