Log Message:
MesaLib18: update to 18.3.1

pkgsrc changes:

- Give up patching both .am/.ac and .in files. It is too complex to maintain.
  Capitulate and depend on autotools.
- more copypasta patches to handle NetBSD-style pthread_setaffinity_np()
- handle PKG_SYSCONFDIR properly
- patch-manual_fdo90311: regened (but untested)
- more to come but the diff is big enough already

New features:
    GL_AMD_depth_clamp_separate on r600, radeonsi.
    GL_AMD_framebuffer_multisample_advanced on radeonsi.
    GL_AMD_gpu_shader_int64 on i965, nvc0, radeonsi.
    GL_AMD_multi_draw_indirect on all GL 4.x drivers.
    GL_AMD_query_buffer_object on i965, nvc0, r600, radeonsi.
    GL_EXT_disjoint_timer_query on radeonsi and most other Gallium drivers (ES \ 
extension)
    GL_EXT_texture_compression_s3tc on all drivers (ES extension)
    GL_EXT_vertex_attrib_64bit on i965, nvc0, radeonsi.
    GL_EXT_window_rectangles on radeonsi.
    GL_KHR_texture_compression_astc_sliced_3d on radeonsi.
    GL_NV_fragment_shader_interlock on i965.
    EGL_EXT_device_base for all drivers.
    EGL_EXT_device_drm for all drivers.
    EGL_MESA_device_software for all drivers.

Bugfixes:

Too many to list