Fix compile of crc32-pclmul_asm on macOS High Sierra

[felixbuenemann]

• .type and .size are ELF/COFF specific so drop them
• .globl + .hidden equivalent for macOS is .private_extern
• assembly symbol names are not mangled on macOS, so we need to add _ prefix

This is similar to #6, but only contains the fixes that are actually required to compile on macOS 10.13.

I have run make test and make test64 and all tests are passing fine.

[vkrasnov]

Can you check https://github.com/cloudflare/zlib/tree/vlad/aarch64 first?

[felixbuenemann]

I tried compiling vlad/aarch64 branch, but it has the same errors as gcc.amd64 branch:

contrib/amd64/crc32-pclmul_asm.S:117:28: error: unknown directive
.globl crc32_pclmul_le_16; .hidden crc32_pclmul_le_16; .type crc32_pclmul_le_16, @function; crc32_pclmul_le_16:
                           ^
contrib/amd64/crc32-pclmul_asm.S:117:56: error: unknown directive
.globl crc32_pclmul_le_16; .hidden crc32_pclmul_le_16; .type crc32_pclmul_le_16, @function; crc32_pclmul_le_16:
                                                       ^
contrib/amd64/crc32-pclmul_asm.S:258:1: error: unknown directive
.size crc32_pclmul_le_16, .-crc32_pclmul_le_16
^
make: *** [crc32-pclmul_asm.o] Error 1

If I cherry-pick c129738 from this PR into vlad/aarch64 compilation works fine and tests are ok.

[vkrasnov]

Ooops, looks like I forgot to commit the fix, only changed the commit message :)

[felixbuenemann]

@vkrasnov Have you found the missing commit for mac compatibility?

[kornelski]

This is still a problem.

[neurolabusc]

@kornelski I solved this by applying @RJVB's Mac and compatibility fixes #6.

While RJVB's code works, it does make some assumptions, e.g. that unsigned int is a 32-bit value. This might not be true for all 16 and 64 bit processors. Therefore, for backward compatibility I would have used the following code to ensure uint8_t, uint32_t, uint64_t are defined.

#ifndef uint32_t 
 #include <stdint.h>
#endif