Alias ZEXTERN, ZEXPORT and ZEXPORTVA to Z_EXTERN, Z_EXPORT and Z_EXPORTVA respectively.

[mtl1979]

See #914.

I chained the defines so any changes to zlib-ng defines are mirrored to stock zlib defines if not overwritten.

[codecov]

Codecov Report

Merging #915 (36f3dd6) into develop (21b0e01) will decrease coverage by 0.76%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop     #915      +/-   ##
===========================================
- Coverage    75.56%   74.80%   -0.77%     
===========================================
  Files           72       74       +2     
  Lines         8172     7854     -318     
  Branches      1350     1368      +18     
===========================================
- Hits          6175     5875     -300     
+ Misses        1480     1432      -48     
- Partials       517      547      +30     

Flag	Coverage Δ
macos_clang	68.65% <ø> (-0.20%)	⬇️
macos_gcc	67.64% <ø> (-0.28%)	⬇️
ubuntu_clang	68.96% <ø> (-0.07%)	⬇️
ubuntu_clang_debug	68.39% <ø> (-0.09%)	⬇️
ubuntu_clang_inflate_allow_invalid_dist	68.89% <ø> (-0.14%)	⬇️
ubuntu_clang_inflate_strict	69.15% <ø> (-0.14%)	⬇️
ubuntu_clang_mmap	68.87% <ø> (-0.17%)	⬇️
ubuntu_clang_msan	69.15% <ø> (-0.14%)	⬇️
ubuntu_gcc	67.15% <ø> (-2.81%)	⬇️
ubuntu_gcc_aarch64	70.13% <ø> (-0.11%)	⬇️
ubuntu_gcc_aarch64_compat_no_opt	67.83% <ø> (-0.15%)	⬇️
ubuntu_gcc_aarch64_no_acle	68.38% <ø> (-0.12%)	⬇️
ubuntu_gcc_aarch64_no_neon	68.07% <ø> (-0.11%)	⬇️
ubuntu_gcc_armhf	70.55% <ø> (-0.12%)	⬇️
ubuntu_gcc_armhf_compat_no_opt	67.79% <ø> (-0.18%)	⬇️
ubuntu_gcc_armhf_no_acle	69.67% <ø> (-0.05%)	⬇️
ubuntu_gcc_armhf_no_neon	69.98% <ø> (-0.06%)	⬇️
ubuntu_gcc_armsf	70.55% <ø> (-0.12%)	⬇️
ubuntu_gcc_armsf_compat_no_opt	67.79% <ø> (-0.18%)	⬇️
ubuntu_gcc_compat_no_opt	69.21% <ø> (-0.11%)	⬇️
ubuntu_gcc_mingw_i686	0.00% <ø> (ø)
ubuntu_gcc_mingw_x86_64	0.00% <ø> (ø)
ubuntu_gcc_no_avx2	69.51% <ø> (-0.10%)	⬇️
ubuntu_gcc_no_pclmulqdq	66.36% <ø> (-0.33%)	⬇️
ubuntu_gcc_no_sse2	67.60% <ø> (-0.35%)	⬇️
ubuntu_gcc_no_sse4	66.32% <ø> (-0.37%)	⬇️
ubuntu_gcc_o3	68.94% <ø> (-0.37%)	⬇️
ubuntu_gcc_osb	?
ubuntu_gcc_ppc	70.99% <ø> (-0.12%)	⬇️
ubuntu_gcc_ppc64	70.18% <ø> (-0.11%)	⬇️
ubuntu_gcc_ppc64le	69.17% <ø> (-0.08%)	⬇️
ubuntu_gcc_s390x	68.36% <ø> (-0.09%)	⬇️
ubuntu_gcc_sparc64	70.88% <ø> (-0.12%)	⬇️
win64_gcc	72.82% <ø> (-0.40%)	⬇️
win64_gcc_compat_no_opt	74.16% <ø> (-0.54%)	⬇️

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

Impacted Files	Coverage Δ
gzwrite.c	48.75% <0.00%> (-4.19%)	⬇️
test/adler32_test.c	60.00% <0.00%> (-3.64%)	⬇️
test/fuzz/minigzip_fuzzer.c	58.33% <0.00%> (-2.66%)	⬇️
gzlib.c	54.47% <0.00%> (-2.52%)	⬇️
test/fuzz/checksum_fuzzer.c	92.00% <0.00%> (-2.24%)	⬇️
test/minideflate.c	57.30% <0.00%> (-2.14%)	⬇️
gzread.c	54.60% <0.00%> (-1.90%)	⬇️
inffast.c	86.52% <0.00%> (-1.75%)	⬇️
crc32_comb.c	80.48% <0.00%> (-1.74%)	⬇️
test/example.c	76.13% <0.00%> (-1.49%)	⬇️
... and 43 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 21b0e01...36f3dd6. Read the comment docs.

[Dead2]

LGTM

[Dead2]

While I now kind of regret it, we do include the other backwards compatible types and defines in zconf-ng.h too, so I guess we should add these there too.
I think we will rather plan to deprecate and remove them again later, once more programs have converted.

[Dead2]

Maybe our porting document should contain a list of all the defines and types that are deprecated and going away, along with the replacement define/type for each of them. Makes it easier for people to do a search for them.

[nmoinvaz]

The reason I don't think it should go in zconf-ng.h is because that API is not intended for it to be zlib-compatible. I think the purpose of the zlib-compat API should be to aid adoption, but not the zlib-ng API. I would be in favor of removing the deprecated types from zlib-ng API sooner rather than later.

[Dead2]

We could start by adding the (gcc) deprecated attribute to the typedefs, that would trigger a warning whenever someone uses one of them.
https://gcc.gnu.org/onlinedocs/gcc-3.2/gcc/Type-Attributes.html

And we could add pragmas trigger warnings when someone uses the defines.
https://stackoverflow.com/questions/2681259/how-to-deprecate-a-macro-in-gcc

[Dead2]

Not having them does mean it would be harder for applications to implement support for both zlib and zlib-ng though.

[mtl1979]

The way this pull request implements the defines is that if someone tries to define using the old names on command-line, it will most likely fail. As such it only allows using the defines as they are defined using the new names in this same file... I was pondering possibility to default value of the new defines based on old defines possibly specified in command line, but that would have made the patch a lot more complex.

We currently don't have macro that hides the differences between compilers in how they declare deprecated macros, functions etc., so marking them as deprecated in non-compat mode would have to be separate pull request.