Fixed conditional compilation to regard headers using dependency files

Makefile

@@ -8,6 +8,7 @@ executable := app
 target := $(buildDir)/$(executable)
 sources := $(call rwildcard,src/,*.cpp)
 objects := $(patsubst src/%, $(buildDir)/%, $(patsubst %.cpp, %.o, $(sources)))
+depends := $(patsubst %.o, %.d, $(objects))
 compileFlags := -std=c++17 -I include
 linkFlags = -L lib/$(platform) -l raylib
 
@@ -78,10 +79,13 @@ lib: submodules
 $(target): $(objects)
 	$(CXX) $(objects) -o $(target) $(linkFlags)
 
+# Add all rules from dependency files
+-include $(depends)
+
 # Compile objects to the build directory
-$(buildDir)/%.o: src/%.cpp
+$(buildDir)/%.o: src/%.cpp Makefile
 	$(MKDIR) $(call platformpth, $(@D))
-	$(CXX) -c $(compileFlags) $< -o $@
+	$(CXX) -MMD -MP -c $(compileFlags) $< -o $@
 
 # Run the executable
 execute: