glew: don't put our CFLAGS into the pkgconfig file

The pkgconfig file doesn't need to know what CFLAGS we're using to build with.

(From OE-Core rev: 50e14c5db88bd523b8b4112476d88b230811393d)

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-graphics/glew/glew/fix-glew.pc-install.patch

@@ -41,6 +41,6 @@ Index: glew-1.11.0/glew.pc.in
 -Libs: -L${libdir} -l@libname@
 -Requires: @requireslib@
 +Version: @VERSION@
-+Cflags: -I${includedir} @CFLAGS@
++Cflags: -I${includedir}
 +Libs: -L${libdir} -lGLEW
 +Requires: glu