fix: windows libc lib paths for x86-windows-msvc

[tangtang95]

Fix windows libc lib paths when compiling to x86-windows-msvc from a x86_64-windows machine. The changes simply consider the cpu arch of the target instead of the host machine. This is what I get when outputting libc for target x86-native-msvc before this fix:

# The directory that contains `stdlib.h`.
# On POSIX-like systems, include directories be found with: `cc -E -Wp,-v -xc /dev/null`
include_dir=C:\Program Files (x86)\Windows Kits\10\Include\10.0.22621.0\ucrt

# The system-specific include directory. May be the same as `include_dir`.
# On Windows it's the directory that includes `vcruntime.h`.
# On POSIX it's the directory that includes `sys/errno.h`.
sys_include_dir=C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\include

# The directory that contains `crt1.o` or `crt2.o`.
# On POSIX, can be found with `cc -print-file-name=crt1.o`.
# Not needed when targeting MacOS.
crt_dir=C:\Program Files (x86)\Windows Kits\10\Lib\10.0.22621.0\ucrt\x64

# The directory that contains `vcruntime.lib`.
# Only needed when targeting MSVC on Windows.
msvc_lib_dir=C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.38.33130\Lib\x86

# The directory that contains `kernel32.lib`.
# Only needed when targeting MSVC on Windows.
kernel32_lib_dir=C:\Program Files (x86)\Windows Kits\10\Lib\10.0.22621.0\um\x64

# The directory that contains `crtbeginS.o` and `crtendS.o`
# Only needed when targeting Haiku.
gcc_dir=

As you can see the path for crt_dir and kernel32_lib_dir ends with x64 which causes errors when lld-link links with system libraries (error: lld-link: libucrtd.lib(stream.obj): machine type x64 conflicts with x86).

I guess this is related to this issue #537?

FYI: I am new to zig. Let me know if there is a procedure for contribution. I don't see it anywhere