build: force Trezor for depends builds

Author: tobtoht

Makefile

@@ -48,7 +48,7 @@ all: release-all
 
 depends:
 	cd contrib/depends && $(MAKE) HOST=$(target) && cd ../.. && mkdir -p build/$(target)/release
-	cd build/$(target)/release && cmake -DCMAKE_TOOLCHAIN_FILE=$(CURDIR)/contrib/depends/$(target)/share/toolchain.cmake ../../.. && $(MAKE)
+	cd build/$(target)/release && USE_DEVICE_TREZOR_MANDATORY=1 cmake -DCMAKE_TOOLCHAIN_FILE=$(CURDIR)/contrib/depends/$(target)/share/toolchain.cmake ../../.. && $(MAKE)
 
 cmake-debug:
 	mkdir -p $(builddir)/debug