Remove remaining CDTs

[hmaarrfk]

Comment:

Moreover, there must be an alternative to the mesa-libEGL(-devel) and mesa-libGL(-devel) CDT packages, as well as having an equivalent to mesa-libGLES(-devel) and mesa-libGLw(-devel) within Conda.

This is needed in order to drop these CDT packages for feedstocks directly needing the CDT Mesa libraries and headers during build without necessarily going through libglvnd.

From: conda-forge/staged-recipes#25919 (comment)

@ehfd identified that there are likely cleanups that can be done on this recipe.

With this prompt, I've noticed we have a few things in yum_requirements.txt that we can remove.

PRs welcome.

[ehfd]

One thing I immediately see is the possibility to switch to xorg-libxxf86vm, an existing non-CDT feedstock.

[ehfd]

The main context of that writing is:

    # We assert that we didn't build screen rendering capabilities.
    # We want on-screen rendering capabilities to be hardware accelerated
    # but that will take more effort

Something needs to supply the libraries that are marked as test ! -f instead of the CDTs. Perhaps it could be a mesalib-stubs package which could be set as a build dependency but not as host or run.

    - test ! -f $PREFIX/lib/dri/kms_swrast_dri${SHLIB_EXT}  # [linux]
    - test ! -f $PREFIX/lib/dri/swrast_dri${SHLIB_EXT}      # [linux]
    - test ! -f $PREFIX/lib/libgbm${SHLIB_EXT}              # [linux]
    - test ! -f $PREFIX/lib/libGLESv1_CM${SHLIB_EXT}        # [linux]
    - test ! -f $PREFIX/lib/libGLESv2${SHLIB_EXT}           # [linux]
    - test ! -f $PREFIX/lib/libEGL${SHLIB_EXT}              # [linux]
    - test ! -f $PREFIX/lib/libGL${SHLIB_EXT}               # [linux]
    - test ! -f $PREFIX/lib/libGLESv1_CM.1${SHLIB_EXT}  # [osx]
    - test ! -f $PREFIX/lib/libGLESv2.2${SHLIB_EXT}     # [osx]
    - test ! -f $PREFIX/lib/libGL.1${SHLIB_EXT}         # [osx]

Edit: As long as libGLdispatch.so.0, libGL.so.1, libEGL.so.1, libGLESv1_CM.so.1, libGLESv2.so.2, libOpenGL.so.0, libGLX.so.0 (not necessarily exhaustive) are provided through libglvnd, I see absolutely no issues with removing the CDT packages. Recent versions of Fedora provide these libraries through glvnd, not mesa so I've missed it while looking at RHEL 7 and 8. - Done in conda-forge/staged-recipes#27107

[ehfd]

After libglvnd has recently become available in conda-forge, libgbm.so.1 + mesa-libglapi should still be built here.

option(
  'gbm',
  type : 'feature',
  deprecated: {'true': 'enabled', 'false': 'disabled'},
  description : 'Build support for gbm platform'
)

option(
  'gbm-backends-path',
  type : 'string',
  value : '',
  description : 'Locations to search for gbm backends, passed as colon ' +
                'separated list. Default: $libdir/gbm.'
)

option(
  'shared-glapi',
  type : 'feature',
  deprecated: {'true': 'enabled', 'false': 'disabled'},
  description : 'Whether to build a shared or static glapi. Defaults to ' +
                'disabled on Windows, enabled elsewhere'
)

Moreover, GLVND support is required to work with the new libglvnd feedstock.

option(
  'glvnd',
  type : 'feature',
  deprecated: {'true': 'enabled', 'false': 'disabled'},
  description : 'Enable GLVND support.'
)

Inclusion of on-screen Mesa libraries can also be fine because there still needs to be a default OpenGL provider, which Ubuntu or Fedora provides as libgl1-mesa, etc... with mesa. This will, then, completely replace the Mesa CDT libraries and integrate with libglvnd.