diff --git a/Makefile.in b/Makefile.in
index 1045f07..0d014e7 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -6,6 +6,7 @@ CXXFLAGS ?=
 AR ?= ar
 RUSTC ?= rustc
 RUSTFLAGS ?=
+EXT_DEPS ?=
 
 RUST_SRC=$(shell find $(VPATH)/. -type f -name '*.rs')
 
@@ -15,11 +16,11 @@ all:	librustalert.dummy
 %.o:	%.c
 	$(CC) $< -o $@ -c $(CFLAGS)
 
-librustalert.dummy: alert.rc $(RUST_SRC)
+librustalert.dummy: alert.rc $(RUST_SRC) $(EXT_DEPS)
 	$(RUSTC) $(RUSTFLAGS) $< --out-dir .
 	touch $@
 
-alert-test: alert.rc $(RUST_SRC)
+alert-test: alert.rc $(RUST_SRC) $(EXT_DEPS)
 	$(RUSTC) $(RUSTFLAGS) $< -o $@ --test
 
 check: alert-test