Fix build if -D_FILE_OFFSET_BITS=64 is set manually.

[mtl1979]

See #923

We renamed ZLIB_INTERNAL to Z_INTERNAL, but forgot to change the test in zlib.h

[codecov]

Codecov Report

Merging #924 (8611aa0) into develop (9f78490) will decrease coverage by 4.95%.
The diff coverage is n/a.

❗ Current head 8611aa0 differs from pull request most recent head 9ac4f95. Consider uploading reports for the commit 9ac4f95 to get more accurate results

@@             Coverage Diff             @@
##           develop     #924      +/-   ##
===========================================
- Coverage    75.49%   70.53%   -4.96%     
===========================================
  Files           74       61      -13     
  Lines         8292     6612    -1680     
  Branches      1369     1137     -232     
===========================================
- Hits          6260     4664    -1596     
+ Misses        1504     1478      -26     
+ Partials       528      470      -58     

Flag	Coverage Δ
macos_clang	?
macos_gcc	?
ubuntu_clang	?
ubuntu_clang_debug	?
ubuntu_clang_inflate_allow_invalid_dist	?
ubuntu_clang_inflate_strict	?
ubuntu_clang_mmap	?
ubuntu_clang_msan	?
ubuntu_gcc	?
ubuntu_gcc_aarch64	?
ubuntu_gcc_aarch64_compat_no_opt	?
ubuntu_gcc_aarch64_no_acle	?
ubuntu_gcc_aarch64_no_neon	?
ubuntu_gcc_armhf	?
ubuntu_gcc_armhf_compat_no_opt	?
ubuntu_gcc_armhf_no_acle	?
ubuntu_gcc_armhf_no_neon	?
ubuntu_gcc_armsf	?
ubuntu_gcc_armsf_compat_no_opt	?
ubuntu_gcc_compat_no_opt	?
ubuntu_gcc_mingw_i686	?
ubuntu_gcc_mingw_x86_64	?
ubuntu_gcc_no_avx2	?
ubuntu_gcc_no_pclmulqdq	?
ubuntu_gcc_no_sse2	?
ubuntu_gcc_no_sse4	?
ubuntu_gcc_o3	?
ubuntu_gcc_osb	70.53% <ø> (ø)
ubuntu_gcc_ppc	?
ubuntu_gcc_ppc64	?
ubuntu_gcc_ppc64le	?
ubuntu_gcc_s390x	?
ubuntu_gcc_sparc64	?
win64_gcc	?
win64_gcc_compat_no_opt	?

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

Impacted Files	Coverage Δ
adler32_p.h	0.00% <0.00%> (-100.00%)	⬇️
arch/x86/chunkset_sse.c	0.00% <0.00%> (-100.00%)	⬇️
arch/x86/adler32_ssse3.c	0.00% <0.00%> (-94.83%)	⬇️
arch/x86/compare258_sse.c	0.00% <0.00%> (-92.00%)	⬇️
arch/x86/slide_sse.c	0.00% <0.00%> (-80.00%)	⬇️
match_tpl.h	0.00% <0.00%> (-71.43%)	⬇️
trees_emit.h	0.00% <0.00%> (-65.83%)	⬇️
trees.c	5.74% <0.00%> (-57.68%)	⬇️
chunkset.c	0.00% <0.00%> (-55.00%)	⬇️
compare258.c	0.00% <0.00%> (-51.62%)	⬇️
... and 59 more

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