Add #include that was needed for older gcc.
Add #include that was needed for older gcc.

h3rb/openshadinglanguage,tectronics/openshadinglanguage,code-google-com/openshadinglanguage,tectronics/openshadinglanguage,qdtk/openshadinglanguage,tectronics/openshadinglanguage,h3rb/openshadinglanguage,code-google-com/openshadinglanguage,tectronics/openshadinglanguage,code-google-com/openshadinglanguage,qdtk/openshadinglanguage,code-google-com/openshadinglanguage,h3rb/openshadinglanguage,qdtk/openshadinglanguage,qdtk/openshadinglanguage,h3rb/openshadinglanguage