title: Makefile - How to call other makefiles with dependencies
body: <p>Hey, I have a simple "master" Makefile who simply calls other makefiles. I'm trying to do the following in order to build components in the right order:</p>
  
  <pre><code>LIB_A = folder_a
  LIB_B = folder_b
  LIB_C = folder_c
  
  MY_TARGETS = $(LIB_A) $(LIB_B) $(LIB_C)
  
  .PHONY: $(LIB_A)
  $(LIB_A):
      @$(MAKE) -C $@;
  
  .PHONY: $(LIB_B)
  $(LIB_B):
      @$(MAKE) -C $@;
  
  .PHONY: $(LIB_C)
  $(LIB_C): $(LIB_A) $(LIB_B)
      @$(MAKE) -C $@;
  
  .PHONY: all 
  all: $(MY_TARGETS)
  </code></pre>
  
  <p>However, when I make, only LIB_A gets built. </p>
  
  <p>(I don't even get a folder_b up-to-date message or whatever).</p>
  
  <p>Any hint ?</p>