title: gcc compiler in cygwin not finding X window directory
body: <p>I'm trying to compile a project that includes various files from X11 in my /usr/include     directory. It compiles fine on a remote linux machine, but when I attempt to run the make file I get the following error:</p>
  
  <pre><code>$ make clean; make
  rm -f xrobot.o mobile_base.o arm.o eye.o object.o 4D_math.o Xkw/Canvas.o Xkw/Sli
  der.o Xkw/Xkw.o lib/simulator.a *~
  cd ./Xkw; make; cd ..; \
  
  make[1]: Entering directory `C:/cygwin/home/Gene/roger/mmRogerSpring2014/RogerSi
  mulator/Xkw'
  gcc -c -g  -I. -I/usr/include/X11 -I/usr/X11R6/include Canvas.c
  Canvas.c:9:22: fatal error: X11/Xos.h: No such file or directory
  compilation terminated.
  make[1]: *** [Canvas.o] Error 1
  make[1]: Leaving directory `C:/cygwin/home/Gene/roger/mmRogerSpring2014/RogerSim
  ulator/Xkw'
  gcc -c -g -I. -I/usr/X11R6/include -I/usr/include/X11 -I./include  xrobot.c
  In file included from xrobot.c:11:0:
  Xkw/Xkw.h:12:27: fatal error: X11/Intrinsic.h: No such file or directory
  compilation terminated.
  make: *** [xrobot.o] Error 1
  </code></pre>
  
  <p>However, I know for a fact that the files are there, I can do </p>
  
  <pre><code>$ cat /usr/include/X11/Xos.h
  </code></pre>
  
  <p>And read the file.</p>
  
  <p>Here is my make file:</p>
  
  <pre><code># replace this with the top of your X11 tree
  # X11 = /exp/rcf/share/X11R5
  X11 = /usr/X11R6
  
  ############## do not change below this line ####################
  
  ROGERINCDIR = ./include
  
  XINCDIR = $(X11)/include
  XLIBDIR = $(X11)/lib 
  EDLAB_XINCDIR = /usr/include/X11
  
  XAWLIB = -lXaw
  XMULIB = -lXmu
  XTOOLLIB = -lXt
  XLIB = -lX11
  XEXTLIB = -lXext
  MATHLIB = -lm
  
  LIBS =  -L$(XLIBDIR) $(XAWLIB) $(XMULIB) $(XTOOLLIB) $(XLIB) $(XEXTLIB) \
      $(MATHLIB)
  
  RM = rm -f
  CC = gcc
  #CCFLAGS = -c -O $(OPT) -I. -I$(XINCDIR)
  CCFLAGS = -c -g -I. -I$(XINCDIR) -I$(EDLAB_XINCDIR) -I$(ROGERINCDIR) 
  
  .SUFFIXES:  .c  .o
  
  .c.o:   
      $(CC) $(CCFLAGS) $&lt;
  
  ############## do not change above this line ####################
  
  ROGERLIB = lib/simulator.a
  
  OFILES1 = xrobot.o \
          mobile_base.o \
          arm.o \
   eye.o \
           object.o \
       4D_math.o
  
  XKWOFILES = Xkw/Canvas.o Xkw/Slider.o Xkw/Xkw.o
  #XKWOFILES = Xkw/Canvas.o Xkw/Xkw.o
  
  HFILES = Roger.h simulate.h control.h modes.h
  
  all:  subdirs  $(OFILES1) $(ROGERLIB)
  
  subdirs:
  cd ./Xkw; make; cd ..; \
  
  #$(ROGERLIB):   $(OFILES1)
  #   $(CC) -o $@ $(OFILES1) $(XKWOFILES) $(LIBS)
  
  $(ROGERLIB):    $(OFILES1) $(XKWOFILES)
      ar r $(ROGERLIB) $(OFILES1) $(XKWOFILES)
  
  clean:
      $(RM) $(OFILES1) $(XKWOFILES) $(ROGERLIB) *~
  
  
  #mobile_base.o: Roger.h simulate.h control.h 
  
  #arm.o: Roger.h simulate.h control.h
  
  #eye.o: Roger.h simulate.h control.h
  
  #object.o:  Roger.h simulate.h control.h
  
  #xrobot.o:  Xkw/Xkw.h Roger.h simulate.h control.h
  
  #tele_interface.o:  Roger.h simulate.h control.h modes.h
  </code></pre>
  
  <p>Edit: I've changed the X11 variable at the top of the make file to be /usr/include instead of /usr/X11R6. It made no difference.</p>
  
  <p>Edit 2: Here's the error with the above mentioned alternative include path.</p>
  
  <pre><code>$ make clean; make
  rm -f xrobot.o mobile_base.o arm.o eye.o object.o 4D_math.o Xkw/Canvas.o Xkw/Sli
  der.o Xkw/Xkw.o lib/simulator.a *~
  cd ./Xkw; make; cd ..; \
  
  make[1]: Entering directory `C:/cygwin/home/Gene/roger/mmRogerSpring2014/RogerSi
  mulator/Xkw'
  gcc -c -g  -I. -I/usr/include/X11 -I/usr/X11R6/include Canvas.c
  Canvas.c:9:22: fatal error: X11/Xos.h: No such file or directory
  compilation terminated.
  make[1]: *** [Canvas.o] Error 1
  make[1]: Leaving directory `C:/cygwin/home/Gene/roger/mmRogerSpring2014/RogerSim
  ulator/Xkw'
  gcc -c -g -I. -I/usr/include/include -I/usr/include/X11 -I./include  xrobot.c
  In file included from xrobot.c:11:0:
  Xkw/Xkw.h:12:27: fatal error: X11/Intrinsic.h: No such file or directory
  compilation terminated.
  make: *** [xrobot.o] Error 1
  </code></pre>