This avoids false positive enabling of w32threads if explicitly
requested on the command line, but dependencies are missing.

This is necessary to avoid GCC assuming MS style printf arguments.

Some pthreads symbols might be present in libc (as shown on various *BSD)
but not all of them, leading to false positives.

Check for the most common compiler flags before the plain symbol check
to avoid known pitfalls.

There are alternate implementations of those libraries that use pthreads.

This enables a more C99-compliant implementation of printf et al.

The MinGW32 project is deprecating its old version macros.

The flag is not unconditionally added to CFLAGS either and the
programs built on the host do not get habitually fed to a debugger.

This enables a more POSIX-compliant printf implementation, that
allows using length modifiers like 'z'.

It was incorrectly moved in c869fcdeac.

Simplifies host/target libc detection splitting.

Add preprocessor flags for API availability as necessary.

Signed-off-by: Diego Biurrun <diego@biurrun.de>

Directly loads AviSynth through LoadLibrary instead of relying on
Video for Windows, and supports using AvxSynth (via dlopen) to
open scripts on Linux and OS X.

Error messages from AviSynth/AvxSynth are now reported through
av_log and exit, rather than the traditional behavior of generating
an error video that the user would need to watch to diagnose.

The main rewrite was authored by d s <avxsynth.testing@gmail.com>
from the AvxSynth team, with additional contributions by

Oka Motofumi <chikuzen.mo@gmail.com>
Stephen Hutchinson <qyot27@gmail.com>
Diego Biurrun <diego@biurrun.de>
Anton Khirnov <anton@khirnov.net>

Signed-off-by: Anton Khirnov <anton@khirnov.net>

Simplifies host/target libc detection splitting.

Certain instrumentation addons leads to a false positive in configure
and link failures at the end of the build phase.

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>

This will check if -wN '..@*' is available and fall back on -x if not;
when none are available, do not run strip at all to prevent removing
functions that might be actually needed.

Signed-off-by: Anton Khirnov <anton@khirnov.net>

Some systems provide Perl without pod2man.

Also add appropriate dependency declarations for perl and texi2html.

This includes moving libavformat/output-example to doc/examples/output.

This allows MSVC 2013 and ICL to build with no external
dependencies.

Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

Perl is needed to build the manual pages, texi2html for the HTML pages.

Msys is unable to convert unix style absolute paths to windows style
paths when combined with certain multichar MSVC options such as
-Fo<file>. We used to work around this issue by passing them as two
separate parameters separated by a space to c99wrap, which then mapped
them back to the actual parameter format that MSVC uses.

The only paths that actually are an issue are absolute unix style
paths, and the only place such absolute paths are used with the output
arguments (-Fo, -Fe, -Fi, -out:) are for the temp files within configure.

By setting TMPDIR to . for msvc/icl builds, we never need to use
absolute unix style paths for the file output, and we can use the
actual proper form of the file output parameters. This avoids requiring
the c99wrap wrapper for remapping the parameters for cases where the
c99 converter isn't invoked at all (MSVC2013 and ICL).

Signed-off-by: Martin Storsjö <martin@martin.st>

ICL doesn't return an error on unknown parameters, and will
always pass the symver_gnu_asm test, and since Windows
never has symbol versioning, just always disable it.

Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

On some platforms (such as msys), symlinks are (poorly) emulated
by simply creating a copy of the file.

This means that when building out of tree, the build tree gets
a copy of the original makefile, which can lead to unintuitive
build errors when the original makefile gets updated later.

Instead simply create a stub makefile which includes the real
one.

Signed-off-by: Martin Storsjö <martin@martin.st>

Originally written by Ronald S. Bultje <rsbultje@gmail.com> and
Clément Bœsch <u@pkh.me>

Further contributions by:
Anton Khirnov <anton@khirnov.net>
Diego Biurrun <diego@biurrun.de>
Luca Barbato <lu_zero@gentoo.org>
Martin Storsjö <martin@martin.st>

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
Signed-off-by: Anton Khirnov <anton@khirnov.net>

MSVC does support enough of C99 to work without the converter since
the 2013 version. Try to detect which version of the compiler in
the path needs to run the C99 converter or not. When the converter
is omitted, compilation time is reduced quite drastically.

Prior to this, users could still use --cc="c99conv -noconv cl"
when running MSVC 2013 to achieve the same.

This checks the version number instead of doing a normal compile
test, since this check needs to be done earlier in configure, before
the normal compile test helpers are usable.

Signed-off-by: Martin Storsjö <martin@martin.st>

As another example of bizarre compiler behavior clang groks the
-Wmaybe-uninitialized option, but not -Wno-maybe-uninitialized
and spews a warning for every file that gets compiled.

HDS fragments basically are FLV fragments wrapped in an ISO
media mdat atom.

Signed-off-by: Martin Storsjö <martin@martin.st>

For some weird reason gcc does not check if the -Wno disabling variants
of warning flags match existing warning flags. Instead it swallows them
silently. That is, unless other warning or error messages are generated,
because then - for some even more bizarre reason - a complaint about the
unknown disable warning flag is issued along with the error or warning
message.

Thus to check for the availability of a warning disabling option, one
needs to check for the enabling variant instead and then add the
disabling variant to CFLAGS.

This is useful to test flags without directly adding them to CFLAGS.

Initially written by Guillaume Martres <smarter@ubuntu.com> as a GSoC
project. Further contributions by the OpenHEVC project and other
developers, namely:

Mickaël Raulet <mraulet@insa-rennes.fr>
Seppo Tomperi <seppo.tomperi@vtt.fi>
Gildas Cocherel <gildas.cocherel@laposte.net>
Khaled Jerbi <khaled_jerbi@yahoo.fr>
Wassim Hamidouche <wassim.hamidouche@insa-rennes.fr>
Vittorio Giovara <vittorio.giovara@gmail.com>
Jan Ekström <jeebjp@gmail.com>
Anton Khirnov <anton@khirnov.net>
Martin Storsjö <martin@martin.st>
Luca Barbato <lu_zero@gentoo.org>
Yusuke Nakamura <muken.the.vfrmaniac@gmail.com>
Reimar Döffinger <Reimar.Doeffinger@gmx.de>
Diego Biurrun <diego@biurrun.de>

Signed-off-by: Anton Khirnov <anton@khirnov.net>

It is by definition unreliable and causes pointless noise on valid
code.

Patch based on x264's AVX2 detection

Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

F4V is Adobe's mp4/iso media variant, with the most significant
addition/change being supporting other flash codecs than just
aac/h264.

Signed-off-by: Martin Storsjö <martin@martin.st>

This is in preparation for removing a .rodata kludge
which was only required for older YASM versions.

The movbe instruction was introduced in 0.8.0, which already
had AVX, which was introduced in 0.7.0, and NASM introduced
movbe in 2.0.3, which is the same version which introduced
AVX support.

Also, make the failure message more accurate.

Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

The implementation of 25cb0c1a involves lots of spurious labels.

The effect of keeping those labels around is making debugging harder.
Those labels are meaningless, and complicate the disassembly. Also,
gdb can't tell the difference between them and function entry points.

This new strip command is irrelevant to any usage of Libav that would
have used the old fully stripped version, because the old one was for
non-debug use.

Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

Qansi-alias worked on 12.x, then caused miscompilation on 13.x, but now
works again passing all FATE tests for icl version 14.

Signed-off-by: Diego Biurrun <diego@biurrun.de>

Prior to this on msvc/icl there was no handling of deprecated functions
and the deprecated warning was disabled.

After enabling there are a number of warnings relating to the CRT and
the use of the non-secure versions of several functions.  Defining
_CRT_SECURE_NO_WARNINGS silences these warnings.

Signed-off-by: Martin Storsjö <martin@martin.st>