Build: rebuild everything when VERSION changes

The version is passed in as a compiler flag, and make doesn't notice a
changed flag. After the bump to 1.1.0, only files whose source had changed
were recompiled, so main.c and log.c still logged 1.0.0 and the app could
show it. Objects now depend on VERSION. Builds from a clean checkout, as CI
does, were never affected.

Makefile

@@ -46,7 +46,9 @@ all: $(ELF)
 $(OBJDIR) build:
 	mkdir -p $@
 
-$(OBJDIR)/%.o: src/%.c | $(OBJDIR)
+# VERSION is compiled into the objects, and make doesn't notice a changed flag,
+# so a new version has to rebuild them.
+$(OBJDIR)/%.o: src/%.c VERSION | $(OBJDIR)
 	$(CC) $(CFLAGS) -c $< -o $@
 
 build/client.c: client/index.html tools/embed_client.py | build

launcher/Makefile

@@ -18,9 +18,10 @@ FONTS := ../vendor/roboto/Roboto-Light.ttf ../vendor/roboto/Roboto-Regular.ttf
 all: package
 $(OUT):
 	mkdir -p $@
-$(OUT)/%.o: %.c | $(OUT)
+# The version is compiled in; a new one must rebuild everything that shows it.
+$(OUT)/%.o: %.c ../VERSION | $(OUT)
 	$(CC) $(CFLAGS) -std=gnu11 -c $< -o $@
-$(OUT)/main.o: main.cpp | $(OUT)
+$(OUT)/main.o: main.cpp ../VERSION | $(OUT)
 	$(CXX) $(CFLAGS) -std=c++17 -fno-exceptions -fno-rtti -c $< -o $@
 $(OUT)/qrcodegen.o: ../vendor/qrcodegen/qrcodegen.c | $(OUT)
 	$(CC) $(CFLAGS) -std=gnu11 -c $< -o $@