Raspberry Pi doesn't have glCheckFrameBufferStatus in ES 1 mode,
same as Android. This was checked in one place but not another,
causing FBOs to not work with 16 bit textures.
Fix for last commit: on RPi glCheckFrameBufferStatus doesn't work
regardless of OpenGL ES version being used (even on ES 2.)
WGL context destruction apparently needs to be done in the thread
that created the context. That code was moved out of the message
pump thread and into the user/main thread. This error was found
using gDebugger (which called it a memory leak.)
Delete debugging printf.
Put ALLEGRO_IPHONE ifdef before ALLEGRO_UNIX since UNIX is
(should it be?) defined on iPhone here. Either way it doesn't
hurt.
Nick Trout fixed a crash in the native dialog addon on iOS
due to threading/TLS issues geting the display.
Fix typo in the al_draw_filled_polygon documentation example
Replace the explict angle calculation with a cross product in the triangulation code.

Results in 30% speedup of al_triangulate_polygon_with_holes.
Nick Trout made iPhone internals headers get installed.
Speed up drawing of the rounds for polylines.

The algorithm is the same as is used by al_calculate_arc, but that function itself could not be used as it was poorly designed and doesn't mesh well with the emitting code used for polylines.
Be a bit paranoid and draw the last triangle with the precise end angle.

This doesn't actually happen with the new code, but the old code produced gaps because of this issue.
Update the "test filled polygon [sw]" unittest to pass with the new round drawing code.

The old code was actually wrong as it produced gaps between the miter and the line, so this is an overall improvement.
Nick Trout added init/shutdown stubs to iOS native dialog addon
so it would compile.
Fix memory leak in _find_executable_file.
Fix prefix of binaries in Android x86 toolchain (NDK r8d).
Add some hints about building Allegro for Android/x86.
speed: Use builtin font.

The removes the dependency on the single external resource a4_font.tga,
as it should be.
audio: Detect OpenSL properly.
audio: Detect OpenSL driver by default.
opensl: Suppress unused variable warnings.