Add support for per-vertex point sizes

This adds a new function to enable per-vertex point size on a
pipeline. This can be set with
cogl_pipeline_set_per_vertex_point_size(). Once enabled the point size
can be set either by drawing with an attribute named
'cogl_point_size_in' or by writing to the 'cogl_point_size_out'
builtin from a snippet.

There is a feature flag which must be checked for before using
per-vertex point sizes. This will only be set on GL >= 2.0 or on GLES
2.0. GL will only let you set a per-vertex point size from GLSL by
writing to gl_PointSize. This is only available in GL2 and not in the
older GLSL extensions.

The per-vertex point size has its own pipeline state flag so that it
can be part of the state that affects vertex shader generation.

Having to enable the per vertex point size with a separate function is
a bit awkward. Ideally it would work like the color attribute where
you can just set it for every vertex in your primitive with
cogl_pipeline_set_color or set it per-vertex by just using the
attribute. This is harder to get working with the point size because
we need to generate a different vertex shader depending on what
attributes are bound. I think if we wanted to make this work
transparently we would still want to internally have a pipeline
property describing whether the shader was generated with per-vertex
support so that it would work with the shader cache correctly.
Potentially we could make the per-vertex property internal and
automatically make a weak pipeline whenever the attribute is bound.
However we would then also need to automatically detect when an
application is writing to cogl_point_size_out from a snippet.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit 8495d9c1c15ce389885a9356d965eabd97758115)

Conflicts:
	cogl/cogl-context.c
	cogl/cogl-pipeline-private.h
	cogl/cogl-pipeline.c
	cogl/cogl-private.h
	cogl/driver/gl/cogl-pipeline-progend-fixed.c
	cogl/driver/gl/gl/cogl-pipeline-progend-fixed-arbfp.c
Use GModule instead of libdl to load unit test symbols

Previously the unit tests were using libdl without directly linking to
it. It looks like this ends up working because one of Cogl's
dependencies ends up pulling adding -ldl via libtool. However in some
configurations it looks like this wasn't happening.

To avoid this problem we can just use GModule to resolve the symbols.
g_module_open is documented to return a handle to the ‘main program’
when NULL is passed as the filename and looking at the code it seems
that this ends up using RTLD_DEFAULT so it will have the same effect.

The in-tree copy of glib already has the code for gmodule so this
shouldn't cause problems for --disable-glib.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit b14ece116ed3e4b18d59b645e77b3449fac51137)
Add test that Cogl doesn't crash when freeing unallocated texture

It looks like Cogl doesn't currently clean up an unallocated atlas
texture properly so if it fails to allocate it. It will then crash
when it is freed. This adds a conformance test to verify that all of
the various texture types can be freed without allocating them.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit bfada22d9a7f60baad5ae5615e45f10327e23e36)
Fix freeing an atlas texture that hasn't been allocated

The free function for atlas textures was previously always assuming
that there will be a valid sub_texture pointer but this might not be
the case if the texture was never successfully allocated. This was
causing Cogl to crash if the application tries to make a texture that
can not fit in the atlas using the automagic texture API.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit a7a8b7aefc8cb03fe8b716bee06b3449a7dba85f)
Use a GList instead of a BSD list for CoglPipelineSnippetList

Previously CoglPipelineSnippetList was using the BSD embedded list
type with a mini struct to combine the list node with a pointer to the
snippet. This is effectively equivalent to just using a GList so we
might as well do that. This will help if we eventually want to get rid
of cogl-queue.h

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit 54a168f3c7829c427d54ab517533bb9f7384d022)
Use the Wayland embedded linked list implementation instead of BSD's

This removes cogl-queue.h and adds a copy of Wayland's embedded list
implementation. The advantage of the Wayland model is that it is much
simpler and so it is easier to follow. It also doesn't require
defining a typedef for every list type.

The downside is that there is only one list type which is a
doubly-linked list where the head has a pointer to both the beginning
and the end. The BSD implementation has many more combinations some of
which we were taking advantage of to reduce the size of critical
structs where we didn't need a pointer to the end of the list.

The corresponding changes to uses of cogl-queue.h are:

• COGL_STAILQ_* was used for onscreen the list of events and dirty
  notifications. This makes the size of the CoglContext grow by one
  pointer.

• COGL_TAILQ_* was used for fences.

• COGL_LIST_* for CoglClosures. In this case the list head now has an
  extra pointer which means CoglOnscreen will grow by the size of
  three pointers, but this doesn't seem like a particularly important
  struct to optimise for size anyway.

• COGL_LIST_* was used for the list of foreign GLES2 offscreens.

• COGL_TAILQ_* was used for the list of sub stacks in a
  CoglMemoryStack.

• COGL_LIST_* was used to track the list of layers that haven't had
  code generated yet while generating a fragment shader for a
  pipeline.

• COGL_LIST_* was used to track the pipeline hierarchy in CoglNode.

The last part is a bit more controversial because it increases the
size of CoglPipeline and CoglPipelineLayer by one pointer in order to
have the redundant tail pointer for the list head. Normally we try to
be very careful about the size of the CoglPipeline struct. Because
CoglPipeline is slice-allocated, this effectively ends up adding two
pointers to the size because GSlice rounds up to the size of two
pointers.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit 13abf613b15f571ba1fcf6d2eb831ffc6fa31324)

Conflicts:
	cogl/cogl-context-private.h
	cogl/cogl-context.c
	cogl/driver/gl/cogl-pipeline-fragend-glsl.c
	doc/reference/cogl-2.0-experimental/Makefile.am
Don't handle the out-of-memory error specially for auto-textures

Previously when trying the three different texture types to create an
automagic texture it would handle the out-of-memory error specially
and bypass trying the remaining texture types. Presumably the idea is
that out-of-memory is a serious error and it can't be recovered from.
However, in the case of atlas textures, this error will be thrown if
the texture is too large to fit into an atlas. In that case it makes
sense to try another texture type so that it can fallback to using a
sliced texture. I think conceptually each different texture type will
have different memory requirements so it seems reasonable to try the
others if there is not enough memory for one of them.

This was causing cogl_texture_new_from_data to break when loading very
large textures because it wouldn't end up slicing them.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit ad6968135a01823eb6a94668dd22c7a4df6f9327)
cogl-fixed: Don't use inline ARM assembler when building for Thumb

There are two asm() statements in cogl-fixed.c that can't be assembled
in Thumb mode. This patch switches it to the generic code in Thumb
mode.

Signed-off-by: Donn Seeley <donn.seeley@windriver.com>
Reviewed-by: Neil Roberts <neil@linux.intel.com>
cogl-fixed: In ARM asm don't allow GCC to reuse input regs for outputs

Add register constraints to prevent asm statement complaints like:

  {standard input}:382: rdhi, rdlo and rm must all be different

Signed-off-by: Donn Seeley <donn.seeley@windriver.com>
Reviewed-by: Neil Roberts <neil@linux.intel.com>