ERROR: Multiple .bb files are due to be built which each provide opencl-headers:###################                                                                                                 | ETA:  0:00:00
  /opt/imx-coral-dev-bsp/sources/meta-openembedded/meta-oe/recipes-core/opencl-headers/opencl-headers_git.bb
  /opt/imx-coral-dev-bsp/sources/meta-freescale/recipes-graphics/imx-gpu-viv/imx-gpu-viv_6.2.4.p4.0-aarch64.bb
A list of tasks depending on these providers is shown and may help explain where the dependency comes from.
/opt/imx-coral-dev-bsp/sources/meta-openembedded/meta-oe/recipes-core/opencl-headers/opencl-headers_git.bb has unique dependees:

/opt/imx-coral-dev-bsp/sources/meta-freescale/recipes-graphics/imx-gpu-viv/imx-gpu-viv_6.2.4.p4.0-aarch64.bb has unique dependees:
  /opt/imx-coral-dev-bsp/sources/poky/meta/recipes-graphics/cairo/cairo_1.16.0.bb:do_prepare_recipe_sysroot
  /opt/imx-coral-dev-bsp/sources/poky/meta/recipes-gnome/gtk+/gtk+3_3.24.8.bb:do_package_write_rpm
  /opt/imx-coral-dev-bsp/sources/poky/meta/recipes-graphics/libepoxy/libepoxy_1.5.3.bb:do_package
  /opt/imx-coral-dev-bsp/sources/poky/meta/recipes-graphics/libepoxy/libepoxy_1.5.3.bb:do_prepare_recipe_sysroot
  /opt/imx-coral-dev-bsp/sources/poky/meta/recipes-gnome/gtk+/gtk+3_3.24.8.bb:do_package
  /opt/imx-coral-dev-bsp/sources/poky/meta/recipes-gnome/gtk+/gtk+3_3.24.8.bb:do_prepare_recipe_sysroot
  /opt/imx-coral-dev-bsp/sources/poky/meta/recipes-graphics/cairo/cairo_1.16.0.bb:do_package
It could be that one recipe provides something the other doesn't and should. The following provider and runtime provider differences may be helpful.
/opt/imx-coral-dev-bsp/sources/meta-openembedded/meta-oe/recipes-core/opencl-headers/opencl-headers_git.bb has unique provides:

/opt/imx-coral-dev-bsp/sources/meta-openembedded/meta-oe/recipes-core/opencl-headers/opencl-headers_git.bb has unique rprovides:
  opencl-headers-staticdev
  opencl-headers-doc
  opencl-headers-dev
  opencl-headers-src
  opencl-headers-locale
  opencl-headers-dbg
  opencl-headers
  ^opencl-headers-locale-.*
/opt/imx-coral-dev-bsp/sources/meta-freescale/recipes-graphics/imx-gpu-viv/imx-gpu-viv_6.2.4.p4.0-aarch64.bb has unique provides:
  virtual/opencl-headers
  virtual/libgl
  virtual/libgbm
  virtual/egl
  virtual/libopenvg
  libgal-imx
  imx-gpu-viv
  virtual/libgles1
  virtual/libgles2
  virtual/opencl-icd
/opt/imx-coral-dev-bsp/sources/meta-freescale/recipes-graphics/imx-gpu-viv/imx-gpu-viv_6.2.4.p4.0-aarch64.bb has unique rprovides:
  ^imx-gpu-viv-locale-.*
  libgles1
  libegl-imx
  libgles1-imx-dev
  libgal-imx
  libvulkan-dev
  libvulkan-imx-dev
  libegl-imx-dev
  libgl-imx
  libegl-dev
  libopenvg-imx
  libwayland-viv-imx
  libopencl-imx-dev
  libgal-imx-dev
  libgles-imx
  libvdk-imx-dev
  imx-gpu-viv-src
  imx-gpu-viv-dbg
  libclc-imx-dev
  libvsc-imx
  imx-gpu-viv-doc
  libglesv2-2
  libgc-wayland-protocol-imx
  libgles2-imx
  imx-gpu-viv-demos
  imx-gpu-viv-tools
  libvulkan-imx
  libgles2-imx-dev
  libgles2
  xf86-video-imx-vivante
  libgbm
  libvivante-dri-imx
  imx-gpu-viv-staticdev
  libclc-imx
  libgles3-dev
  libvulkan
  imx-gpu-viv
  libgles3-imx-dev
  libopencl-imx
  libgl
  libwayland-viv-imx-dev
  libopenvx-imx-dev
  imx-gpu-viv-dev
  libgc-wayland-protocol-imx-dev
  libgbm-dev
  libgl1
  imx-gpu-viv-locale
  libglesv1-cm1
  libglslc-imx-dev
  libglslc-imx
  libgl-dev
  libopenvg-imx-dev
  libgl-imx-dev
  libgbm-imx
  libgles2-dev
  libegl1
  libgles1-imx
  libgles-imx-devlibgles1-dev
  libopenvx-imx
Initialising tasks: 100% |##########################################################################################################################################################################| Time: 0:00:01
Sstate summary: Wanted 14 Found 0 Missed 14 Current 765 (0% match, 98% complete)
NOTE: Executing Tasks
NOTE: Setscene tasks completed
WARNING: opencv-4.1.2.imx-r0 do_fetch: Failed to fetch URL git://source.codeaurora.org/external/imx/opencv-imx.git;protocol=https;branch=4.1.2_imx;name=opencv, attempting MIRRORS if available
ERROR: opencv-4.1.2.imx-r0 do_fetch: Fetcher failure: Unable to find revision c5bf3ec2e791e0817ab1d5880e78711b6fe08206 in branch 4.1.2_imx even from upstream
ERROR: opencv-4.1.2.imx-r0 do_fetch: Fetcher failure for URL: 'git://source.codeaurora.org/external/imx/opencv-imx.git;protocol=https;branch=4.1.2_imx;name=opencv'. Unable to fetch URL from any source.
ERROR: Logfile of failure stored in: /opt/imx-coral-dev-bsp/build/tmp/work/aarch64-mx8m-fslc-linux/opencv/4.1.2.imx-r0/temp/log.do_fetch.36984
ERROR: Task (/opt/imx-coral-dev-bsp/sources/meta-freescale/recipes-support/opencv/opencv_4.1.2.imx.bb:do_fetch) failed with exit code '1'