title: With autoconf/automake, how do I specify include file paths?
body: <p>Let's say I want to have the generate makefile pass some specific header paths to g++.</p>
  
  <p>What do I need to add to configure.ac or Makefile.am to specify this?</p>
  
  <p>(note - I do not want to pass it in the CPPFLAGS with ./configure.  I want those paths baked in before that step)</p>
  
  <p>EDIT:
  Specifically, I want to to include let's say /usr/include/freetype and /mypath/include.</p>
  
  <p>I put AC_CHECK_HEADERS([freetype/config/ftheader.h]) and it passes, but doesn't seem to add it to the -I passed to g++.</p>
  
  <p>I also did try adding CPPFLAGS=-I.:/usr/include/freetype:/mypath/include, but it screws up and puts -I twice, the first as -I. and it ignores the 2nd -I.</p>