[MacOS] Downgrade to XCode 11.7.0 for pkgcheck.

[mtl1979]

XCode 12.1.1 was removed from CI, so pkgcheck tests started to fail. We need older version, because support for ZERO_AR_DATE variable was removed in more recent versions.

[codecov]

Codecov Report

Merging #1056 (cfabc7c) into develop (c762db1) will increase coverage by 0.01%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop    #1056      +/-   ##
===========================================
+ Coverage    81.55%   81.56%   +0.01%     
===========================================
  Files           85       85              
  Lines         8667     8667              
  Branches      1398     1398              
===========================================
+ Hits          7068     7069       +1     
  Misses        1057     1057              
+ Partials       542      541       -1     

Flag	Coverage Δ
macos_clang	70.19% <ø> (ø)
macos_gcc	68.48% <ø> (ø)
ubuntu_clang	75.42% <ø> (ø)
ubuntu_clang_debug	75.54% <ø> (ø)
ubuntu_clang_inflate_allow_invalid_dist	75.15% <ø> (ø)
ubuntu_clang_inflate_strict	75.36% <ø> (ø)
ubuntu_clang_mmap	75.39% <ø> (ø)
ubuntu_clang_msan	75.42% <ø> (ø)
ubuntu_clang_pigz	36.16% <ø> (ø)
ubuntu_clang_pigz_no_optim	40.92% <ø> (ø)
ubuntu_clang_pigz_no_threads	35.66% <ø> (ø)
ubuntu_clang_reduced_mem	75.68% <ø> (ø)
ubuntu_gcc	74.82% <ø> (ø)
ubuntu_gcc_aarch64	76.71% <ø> (ø)
ubuntu_gcc_aarch64_compat_no_opt	74.49% <ø> (ø)
ubuntu_gcc_aarch64_no_acle	76.16% <ø> (ø)
ubuntu_gcc_aarch64_no_neon	76.48% <ø> (ø)
ubuntu_gcc_armhf	76.71% <ø> (ø)
ubuntu_gcc_armhf_compat_no_opt	74.45% <ø> (ø)
ubuntu_gcc_armhf_no_acle	76.99% <ø> (ø)
ubuntu_gcc_armhf_no_neon	77.27% <ø> (ø)
ubuntu_gcc_armsf	76.72% <ø> (ø)
ubuntu_gcc_armsf_compat_no_opt	74.45% <ø> (ø)
ubuntu_gcc_compat_no_opt	75.44% <ø> (ø)
ubuntu_gcc_compat_sprefix	74.73% <ø> (ø)
ubuntu_gcc_mingw_i686	0.00% <ø> (ø)
ubuntu_gcc_mingw_x86_64	0.00% <ø> (ø)
ubuntu_gcc_no_avx2	76.78% <ø> (ø)
ubuntu_gcc_no_ctz	77.67% <ø> (ø)
ubuntu_gcc_no_ctzll	77.34% <ø> (ø)
ubuntu_gcc_no_pclmulqdq	73.56% <ø> (ø)
ubuntu_gcc_no_sse2	76.04% <ø> (ø)
ubuntu_gcc_no_sse4	73.91% <ø> (ø)
ubuntu_gcc_o3	74.03% <ø> (ø)
ubuntu_gcc_osb	76.81% <ø> (ø)
ubuntu_gcc_pigz	36.53% <ø> (+0.02%)	⬆️
ubuntu_gcc_pigz_aarch64	38.60% <ø> (+0.03%)	⬆️
ubuntu_gcc_ppc	74.51% <ø> (ø)
ubuntu_gcc_ppc64	77.55% <ø> (ø)
ubuntu_gcc_ppc64le	76.01% <ø> (ø)
ubuntu_gcc_ppc_no_power8	77.31% <ø> (ø)
ubuntu_gcc_s390x	78.64% <ø> (ø)
ubuntu_gcc_sparc64	78.58% <ø> (ø)
ubuntu_gcc_sprefix	74.51% <ø> (ø)
win64_gcc	∅ <ø> (∅)
win64_gcc_compat_no_opt	∅ <ø> (∅)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
trees.c	96.44% <0.00%> (+0.27%)	⬆️

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