Move frozen to its own subdir

unittest/Makefile

@@ -9,16 +9,16 @@ INCLUDE = ../include
 default: $(TARGET)
 all: default
 
-OBJ_WIDGET = $(patsubst %.c, %.o, $(wildcard *.c))
+OBJECTS = $(patsubst %.c, %.o, $(wildcard *.c)) frozen/frozen.o
 HEADERS = $(wildcard *.h)
 
 %.o: %.c $(HEADERS)
 	$(CC) $(CFLAGS) -I$(INCLUDE) -c $< -o $@
 
-.PRECIOUS: $(TARGET) $(OBJ_WIDGET)
+.PRECIOUS: $(TARGET) $(OBJECTS)
 
-$(TARGET): $(OBJ_WIDGET)
+$(TARGET): $(OBJECTS)
-	$(CC) $(CFLAGS) -I$(INCLUDE) $(OBJ_WIDGET) $(LIBS) -o $@
+	$(CC) $(CFLAGS) -I$(INCLUDE) $(OBJECTS) $(LIBS) -o $@
 
 clean:
 	-rm -f *.o

unittest/test.h

@@ -3,7 +3,7 @@
 
 #include <stdlib.h>
 #include <string.h>
-#include "frozen.h"
+#include "frozen/frozen.h"
 #include "mgos_mock.h"
 
 int test_widget(void);