vo_opengl: refactor shader generation (part 2)

This adds stuff related to gamma, linear light, sigmoid, BT.2020-CL,
etc, as well as color management. Also adds a new gamma function (gamma22).

This adds new parameters to configure the CMS settings, in particular
letting us target simple colorspaces without requiring usage of a 3DLUT.

This adds smoothmotion. Mostly working, but it's still sensitive to
timing issues. It's based on an actual queue now, but the queue size
is kept small to avoid larger amounts of latency.

Also makes “upscale before blending” the default strategy.
This is justified because the "render after blending" thing doesn't seme
to work consistently any way (introduces stutter due to the way vsync
timing works, or something), so this behavior is a bit closer to master
and makes pausing/unpausing less weird/jumpy.

This adds the remaining scalers, including bicubic_fast, sharpen3,
sharpen5, polar filters and antiringing. Apparently, sharpen3/5 also
consult scale-param1, which was undocumented in master.

This also implements cropping and chroma transformation, plus
rotation/flipping. These are inherently part of the same logic, although
it's a bit rough around the edges in some case, mainly due to the fallback
code paths (for bilinear scaling without indirection).

DOCS/man/vo.rst

@@ -352,6 +352,10 @@ Available video output drivers are:
             blurrier. Defaults to 1. Note that setting this too low (eg. 0.5)
             leads to bad results. It's recommended to stay between 0.9 and 1.1.
 
+        ``sharpen3``, ``sharpen5``
+            Sharpening strength. Increasing this makes the image sharper but
+            adds more ringing and aliasing. Defaults to 0.5.
+
     ``scale-radius=<r>``
         Set radius for filters listed below, must be a float number between 1.0
         and 16.0. Defaults to be 3.0 if not specified.
@@ -377,21 +381,6 @@ Available video output drivers are:
         will reproduce the source image perfectly if no scaling is performed.
         Note that this option never affects ``cscale``.
 
-    ``srgb``
-        Convert and color correct the output to sRGB before displaying it on
-        the screen. This option enables ``linear-scaling``.
-
-        This option is equivalent to using ``icc-profile`` with an sRGB ICC
-        profile, but it is implemented without a 3DLUT and does not require
-        LittleCMS 2. If both ``srgb`` and ``icc-profile`` are present, the
-        latter takes precedence, as they are somewhat redundant.
-
-        Note: When playing back BT.2020 content with this option enabled, out
-        of gamut colors will be numerically clipped, which can potentially
-        change the hue and/or luminance. If this is not desired, it is
-        recommended to use ``icc-profile`` with an sRGB ICC profile instead,
-        when playing back wide-gamut BT.2020 content.
-
     ``pbo``
         Enable use of PBOs. This is slightly faster, but can sometimes lead to
         sporadic and temporary image corruption (in theory, because reupload
@@ -460,9 +449,10 @@ Available video output drivers are:
         ``scale-antiring``.
 
     ``linear-scaling``
-        Scale in linear light. This is automatically enabled if ``srgb``,
-        ``icc-profile`` or ``sigmoid-upscaling`` is set. It should only
-        be used with a ``fbo-format`` that has at least 16 bit precision.
+        Scale in linear light. This is automatically enabled if
+        ``target-prim``, ``target-trc``, ``icc-profile`` or
+        ``sigmoid-upscaling`` is set. It should only be used with a
+        ``fbo-format`` that has at least 16 bit precision.
 
     ``fancy-downscaling``
         When using convolution based filters, extend the filter size
@@ -553,13 +543,44 @@ Available video output drivers are:
 
         NOTE: Only implemented on OS X.
 
+    ``target-prim=<value>``
+        Specifies the primaries of the display. Video colors will be adapted
+        to this colorspace if necessary. Valid values are:
+
+        auto
+            Disable any adaptation (default)
+        bt470m
+            ITU-R BT.470 M
+        bt601-525
+            ITU-R BT.601 (525-line SD systems, eg. NTSC), SMPTE 170M/240M
+        bt601-625
+            ITU-R BT.601 (625-line SD systems, eg. PAL/SECAM), ITU-R BT.470 B/G
+        bt709
+            ITU-R BT.709 (HD), IEC 61966-2-4 (sRGB), SMPTE RP177 Annex B
+        bt2020
+            ITU-R BT.2020 (UHD)
+
+    ``target-trc=<value>``
+        Specifies the transfer characteristics (gamma) of the display. Video
+        colors will be adjusted to this curve. Valid values are:
+
+        auto
+            Disable any adaptation (default)
+        bt1886
+            ITU-R BT.1886 curve, without the brightness drop (approx. 1.961)
+        srgb
+            IEC 61966-2-4 (sRGB)
+        linear
+            Linear light output
+        gamma22
+            Pure power curve (gamma 2.2)
+
     ``icc-profile=<file>``
         Load an ICC profile and use it to transform linear RGB to screen output.
-        Needs LittleCMS 2 support compiled in. This option overrides the ``srgb``
-        property, as using both is somewhat redundant. It also enables
+        Needs LittleCMS 2 support compiled in. This option overrides the
+        ``target-prim`` and ``target-trc`` options. It also enables
         ``linear-scaling``.
 
-
     ``icc-profile-auto``
         Automatically select the ICC display profile currently specified by
         the display settings of the operating system.
@@ -573,9 +594,8 @@ Available video output drivers are:
         Its size depends on the ``3dlut-size``, and can be very big.
 
     ``icc-intent=<value>``
-        Specifies the ICC Intent used for transformations between color spaces.
-        This affects the rendering when using ``icc-profile`` or ``srgb`` and
-        also affects the way DCP XYZ content gets converted to RGB.
+        Specifies the ICC intent used for the color transformation (when using
+        ``icc-profile``).
 
         0
             perceptual