message: Fix checking of header timestamps.
  This is implemented in such a way that a change in one of our headers
  won't cause recompilation of large C dependancies. It's a bit hacky, but
  it works.
diff: @@ -89,6 +89,8 @@ CXXOBJ=$(CXXSRC:.cpp=.o)
  OBJ=$(COBJ) $(CXXOBJ)
  +HDR=$(CHDR) $(CXXHDR)
  +
  all: $(SERVER)
  windows: $(SERVER)
  @@ -103,12 +105,15 @@ windows : SERVER=$(WIN_SERVER)
  .SUFFIX: .o .c .cpp .h .hpp
  -.c.o: $(CHDR)
  +.c.o:
  $(CC) -c $(CFLAGS) -o $@ $<
  -.cpp.o: $(CXXHDR)
  +.cpp.o:
  $(CXX) -c $(CXXFLAGS) -o $@ $<
  +# header timestamps are a prerequisite for OF object files
  +$(CXXOBJ): $(CXXHDR)
  +
  $(SERVER): $(OBJ) $(CHDR) $(CXXHDR)
  mkdir -p bin
  $(CXX) $(OBJ) $(LDFLAGS) -o $(SERVER)
  