macosx: fixed NSRangeException when triggering modifier keys without characters as enabled by some international keyboards (close #7268)

If the sample per packet is wrong, denote to qt_version 0

Ref: http://forum.videolan.org/viewtopic.php?f=14&t=103013

This accounts for sporadic assert failed at vlc termination.

This will be used later.

Hardware floating point must be enabled explicitly.

This also removes the NEON_CFLAGS substition variable and the check for
ARMv6, neither of which are anymore not used.

minizip should not and cannot be compiled without zlib.

extras/package: iOS: enable thumb for compilation, clean up the AS definitions and disable freetype for now

Should be tested on Android/Linux.

Thanks to Mans Rullgard for the help.

if a logo is bigger than a video and if positioning results in negative
offsets, vlc crashes in the blend function.

This patch adds a warning, and offset is forced to 0 if negative.

Note that a bigger logo is not a problem per se. (Blend truncates the logo).
Only offsetting it with negative values was a problem.

Also update avcodec encoder and switcher x86 checks.

Pointed-out-by: Michał Trzebiatowski <hippie_1968@hotmail.com>

Signed-off-by: Christoph Miebach <christoph.miebach@web.de>

This matches a similar problem on x264: http://mailman.videolan.org/pipermail/x264-devel/2012-January/009073.html