targets/opencl: add build-time conflict for LLVM 10.0.0

LLVM 10.0.0 required static linking of Polly otherwise compilation
failed. LLVM 10.0.1 statically links Polly to libLLVM which causes
issues such as #3494 due to Polly being present in multiple libraries.
As a solution drop static Polly linking and conflict with the only LLVM
version which requires it.
75 jobs for !6876 with master
latest detached
Status Job ID Name Coverage
  Container+Docs
manual #4698730
aarch64 manual
arm_build
manual #4698733
manual
arm_test-base
manual #4698724
manual
x86_build-base
manual #4698728
manual
x86_build_old
manual #4698726
manual
x86_test-base
 
  Container 2
created #4698751
arm64_test
created #4698742
i386_build
created #4698735
kernel+rootfs_amd64
created #4698736
aarch64
kernel+rootfs_arm64
created #4698738
aarch64
kernel+rootfs_armhf
created #4698744
ppc64el_build
created #4698746
s390x_build
created #4698740
x86_build
created #4698747
x86_test-gl
created #4698749
x86_test-vk
 
  Meson X86 64
created #4698759
meson-android
created #4698761
meson-clang
created #4698757
meson-classic
created #4698762
meson-clover
created #4698754
meson-gallium
created #4698756
meson-release
created #4698753
meson-testing
created #4698764
meson-vulkan
 
  Scons
created #4698766
allowed to fail
scons-win64
 
  Meson Misc
created #4698770
aarch64
meson-arm64
created #4698772
aarch64
meson-arm64-build-test
created #4698768
aarch64
meson-armhf
created #4698774
meson-i386
created #4698779
meson-mingw32-x86_64
created #4698777
kvm
meson-ppc64el
created #4698775
kvm
meson-s390x
 
  Llvmpipe
created #4698786
llvmpipe-gles2
created #4698788
llvmpipe-traces
created #4698783
piglit-glslparser
created #4698781
piglit-quick_gl
created #4698784
piglit-quick_shader
 
  Softpipe
created #4698797
softpipe-gl
created #4698790
softpipe-gles2
created #4698791
softpipe-gles3
created #4698793
softpipe-gles31 1/2
created #4698795
softpipe-gles31 2/2
 
  Freedreno
created #4698821
google-freedreno-db410c
arm64_a306_gles2
created #4698822
google-freedreno-db410c
arm64_a306_gles3
created #4698823
google-freedreno-db410c
arm64_a306_gles3_options
created #4698824
google-freedreno-db820c
arm64_a530_gles2
created #4698825
google-freedreno-db820c
arm64_a530_gles3
created #4698826
google-freedreno-db820c
arm64_a530_gles31
created #4698810
google-freedreno-cheza
arm64_a630_bypass
created #4698816
google-freedreno-cheza
arm64_a630_gl
created #4698800
google-freedreno-cheza
arm64_a630_gles2
created #4698805
google-freedreno-cheza
arm64_a630_gles3
created #4698802
google-freedreno-cheza
arm64_a630_gles31
created #4698814
google-freedreno-cheza
arm64_a630_gmem
created #4698807
google-freedreno-cheza
arm64_a630_noubo
created #4698812
google-freedreno-cheza
arm64_a630_traces
created #4698818
google-freedreno-cheza
arm64_a630_vk
created #4698820
google-freedreno-cheza
arm64_a630_vk_sysmem
 
  Panfrost
created #4698827
mesa-ci-aarch64-lava-collabora
panfrost-t720-gles2:arm64
created #4698828
mesa-ci-aarch64-lava-collabora
panfrost-t760-gles2:armhf
created #4698829
mesa-ci-aarch64-lava-collabora
panfrost-t860-gles2:arm64
created #4698830
mesa-ci-aarch64-lava-collabora
panfrost-t860-gles3:arm64 1/2
created #4698831
mesa-ci-aarch64-lava-collabora
panfrost-t860-gles3:arm64 2/2
created #4698832
mesa-ci-aarch64-lava-collabora
panfrost-t860-traces:arm64
 
  Virgl
created #4698837
virgl-gl30-on-gl
created #4698838
virgl-gl31-on-gl
created #4698839
virgl-gl32-on-gl
created #4698833
virgl-gles2-on-gl
created #4698835
virgl-gles31-on-gl 1/2
created #4698836
virgl-gles31-on-gl 2/2
created #4698834
virgl-gles3-on-gl
created #4698840
virgl-traces
 
  Radeonsi
created #4698841
mesa-ci-aarch64-lava-collabora
radeonsi-stoney-gles2:amd64
created #4698843
mesa-ci-aarch64-lava-collabora
radeonsi-stoney-gles31:amd64
created #4698842
mesa-ci-aarch64-lava-collabora
radeonsi-stoney-gles3:amd64
created #4698844
mesa-ci-aarch64-lava-collabora
radeonsi-stoney-traces:amd64