`#if defined(_MSC_VER)` is not sufficient to detect "building for Windows"

[linusg]

This breaks when using the Zig toolchain to (cross-)compile for Windows, for instance.

/home/linus/.cache/zig/p/1220548d4c0c4895ae0b0d3e8e4c66bae071d069f8405f8e3812b6c122e3fe0c7fe4/cutils.c:660:7: error: call to undeclared function 'clock_gettime'; ISO C99 and later do not support implicit function declarations
  if (clock_gettime(CLOCK_MONOTONIC, &t))
      ^
/home/linus/.cache/zig/p/1220548d4c0c4895ae0b0d3e8e4c66bae071d069f8405f8e3812b6c122e3fe0c7fe4/cutils.c:660:21: error: use of undeclared identifier 'CLOCK_MONOTONIC'
  if (clock_gettime(CLOCK_MONOTONIC, &t))
                    ^

[linusg]

Patching in a #define _MSC_VER reveals a few more issue that were not present in the original quickjs:

/nix/store/l957vh49c3mqn19h4b3mqa33lim69hmb-zig-0.12.0-dev.1800+559e216f3/lib/include/inttypes.h:18:2: error: MSVC does not have inttypes.h prior to Visual Studio 2013
#error MSVC does not have inttypes.h prior to Visual Studio 2013
 ^
/home/linus/.cache/zig/p/1220548d4c0c4895ae0b0d3e8e4c66bae071d069f8405f8e3812b6c122e3fe0c7fe4/libunicode.c:30:10: note: in file included from /home/linus/.cache/zig/p/1220548d4c0c4895ae0b0d3e8e4c66bae071d069f8405f8e3812b6c122e3fe0c7fe4/libunicode.c:30:
#include "cutils.h"
         ^
/home/linus/.cache/zig/p/1220548d4c0c4895ae0b0d3e8e4c66bae071d069f8405f8e3812b6c122e3fe0c7fe4/cutils.h:29:10: note: in file included from /home/linus/.cache/zig/p/1220548d4c0c4895ae0b0d3e8e4c66bae071d069f8405f8e3812b6c122e3fe0c7fe4/cutils.h:29:
#include <inttypes.h>
         ^

/nix/store/l957vh49c3mqn19h4b3mqa33lim69hmb-zig-0.12.0-dev.1800+559e216f3/lib/libc/include/any-windows-any/winsock2.h:15:2: error: Please include winsock2.h before windows.h
#warning Please include winsock2.h before windows.h
 ^
/home/linus/.cache/zig/p/1220548d4c0c4895ae0b0d3e8e4c66bae071d069f8405f8e3812b6c122e3fe0c7fe4/libunicode.c:30:10: note: in file included from /home/linus/.cache/zig/p/1220548d4c0c4895ae0b0d3e8e4c66bae071d069f8405f8e3812b6c122e3fe0c7fe4/libunicode.c:30:
#include "cutils.h"
         ^
/home/linus/.cache/zig/p/1220548d4c0c4895ae0b0d3e8e4c66bae071d069f8405f8e3812b6c122e3fe0c7fe4/cutils.h:36:10: note: in file included from /home/linus/.cache/zig/p/1220548d4c0c4895ae0b0d3e8e4c66bae071d069f8405f8e3812b6c122e3fe0c7fe4/cutils.h:36:
#include <winsock2.h>
         ^

/home/linus/.cache/zig/p/1220548d4c0c4895ae0b0d3e8e4c66bae071d069f8405f8e3812b6c122e3fe0c7fe4/cutils.h:38:9: error: 'alloca' macro redefined
#define alloca _alloca
        ^
/home/linus/.cache/zig/p/1220548d4c0c4895ae0b0d3e8e4c66bae071d069f8405f8e3812b6c122e3fe0c7fe4/libunicode.c:30:10: note: in file included from /home/linus/.cache/zig/p/1220548d4c0c4895ae0b0d3e8e4c66bae071d069f8405f8e3812b6c122e3fe0c7fe4/libunicode.c:30:
#include "cutils.h"
         ^
/nix/store/l957vh49c3mqn19h4b3mqa33lim69hmb-zig-0.12.0-dev.1800+559e216f3/lib/libc/include/any-windows-any/malloc.h:159:9: note: previous definition is here
#define alloca(x) __builtin_alloca((x))
        ^

[saghul]

That define is not for detecting windows but the compiler. The mingw tool chain for example is also windows, but it does provide clock_gettime.

What does the Zig compiler target?

[linusg]

ah, I see - Zig targets mingw-w64 by default (or when using a triple like x86_64-windows-gnu, ziglang/zig#8878). It appears the actual availability of clock_gettime depends on a couple of conditions, which are probably not being met in this case?

https://github.com/ziglang/zig/blob/69195d0cd43468f213332c5792df04c941f8313d/lib/libc/include/any-windows-any/time.h#L318

[saghul]

We do define _GNU_SOURCE which I think should do it?

[linusg]

After further investigation this seems to be a shortcoming of the Zig toolchain itself, which ships a stub header for MinGW's pthread_time.h, hence the missing definitions:

https://github.com/ziglang/zig/blob/master/lib/libc/include/any-windows-any/pthread_time.h

I worked around that using https://github.com/kassane/winpthreads-zigbuild. Sorry for the noise :)

[saghul]

No worries, glad you sorted it out!