title: How to define several include path in Makefile
body: <p>New to C++; Basic understanding of includes, libraries and the compile process. Did a few simple makefiles yet.</p>
  
  <p>My current project involves using an informix DB api and i need to include header files in more than one nonstandard dirs. How to write that ? Havent found anything on the net, probably because i did not use good search terms</p>
  
  <p>This is one way what i tried (not working). Just to show the makefile </p>
  
  <pre><code>LIB=-L/usr/informix/lib/c++
  INC=-I/usr/informix/incl/c++ /opt/informix/incl/public
  
  default:    main
  
  main:   test.cpp
          gcc -Wall $(LIB) $(INC) -c test.cpp
          #gcc -Wall $(LIB) $(INC) -I/opt/informix/incl/public -c test.cpp
  
  clean:
          rm -r test.o make.out
  </code></pre>