qemu_pipe: fix Mac build error.

The <hardware/qemu_pipe.h> header was missing an include
that causes the code under development/tools/emulator/opengl
to fail to compile on OS X.

You need to define BUILD_EMULATOR_OPENGL=true in your
environment, otherwise this code doesn't get built yet by default.

Change-Id: Ia1b48c0ab84f493f3c9f95030d9165961069fb6e
1 file changed