implemented runtime abi detetction for windows

src/os.cpp

@@ -1125,29 +1125,27 @@ Error os_get_cwd(Buf *out_cwd) {
 #endif
 }
 
-#if defined(ZIG_OS_WINDOWS)
 #define is_wprefix(s, prefix) \
     (wcsncmp((s), (prefix), sizeof(prefix) / sizeof(WCHAR) - 1) == 0)
-static bool is_stderr_cyg_pty(void) {
-    HANDLE stderr_handle = GetStdHandle(STD_ERROR_HANDLE);
-    if (stderr_handle == INVALID_HANDLE_VALUE)
+bool ATTRIBUTE_MUST_USE os_is_cygwin_pty(int fd) {
+#if defined(ZIG_OS_WINDOWS)
+    HANDLE handle = (HANDLE)_get_osfhandle(fd);
+    
+    // Cygwin/msys's pty is a pipe.
+    if (handle == INVALID_HANDLE_VALUE || GetFileType(handle) != FILE_TYPE_PIPE) {
         return false;
+    }
 
     int size = sizeof(FILE_NAME_INFO) + sizeof(WCHAR) * MAX_PATH;
-    FILE_NAME_INFO *nameinfo;
     WCHAR *p = NULL;
-
-    // Cygwin/msys's pty is a pipe.
-    if (GetFileType(stderr_handle) != FILE_TYPE_PIPE) {
-        return 0;
-    }
-    nameinfo = (FILE_NAME_INFO *)allocate<char>(size);
+    
+    FILE_NAME_INFO *nameinfo = (FILE_NAME_INFO *)allocate<char>(size);
     if (nameinfo == NULL) {
-        return 0;
+        return false;
     }
     // Check the name of the pipe:
     // '\{cygwin,msys}-XXXXXXXXXXXXXXXX-ptyN-{from,to}-master'
-    if (GetFileInformationByHandleEx(stderr_handle, FileNameInfo, nameinfo, size)) {
+    if (GetFileInformationByHandleEx(handle, FileNameInfo, nameinfo, size)) {
         nameinfo->FileName[nameinfo->FileNameLength / sizeof(WCHAR)] = L'\0';
         p = nameinfo->FileName;
         if (is_wprefix(p, L"\\cygwin-")) {      /* Cygwin */
@@ -1180,12 +1178,14 @@ static bool is_stderr_cyg_pty(void) {
     }
     free(nameinfo);
     return (p != NULL);
-}
+#else
+    return false
 #endif
+}
 
 bool os_stderr_tty(void) {
 #if defined(ZIG_OS_WINDOWS)
-    return _isatty(_fileno(stderr)) != 0 || is_stderr_cyg_pty();
+    return _isatty(_fileno(stderr)) != 0 || os_is_cygwin_pty(_fileno(stderr));
 #elif defined(ZIG_OS_POSIX)
     return isatty(STDERR_FILENO) != 0;
 #else
@@ -1486,7 +1486,7 @@ WORD original_console_attributes = FOREGROUND_RED|FOREGROUND_GREEN|FOREGROUND_BL
 
 void os_stderr_set_color(TermColor color) {
 #if defined(ZIG_OS_WINDOWS)
-    if (is_stderr_cyg_pty()) {
+    if (os_stderr_tty()) {
         set_color_posix(color);
         return;
     }

src/os.hpp

@@ -11,6 +11,7 @@
 #include "list.hpp"
 #include "buffer.hpp"
 #include "error.hpp"
+#include "target.hpp"
 #include "zig_llvm.h"
 #include "windows_sdk.h"
 
@@ -152,6 +153,8 @@ Error ATTRIBUTE_MUST_USE os_get_win32_ucrt_include_path(ZigWindowsSDK *sdk, Buf
 Error ATTRIBUTE_MUST_USE os_get_win32_ucrt_lib_path(ZigWindowsSDK *sdk, Buf *output_buf, ZigLLVM_ArchType platform_type);
 Error ATTRIBUTE_MUST_USE os_get_win32_kern32_path(ZigWindowsSDK *sdk, Buf *output_buf, ZigLLVM_ArchType platform_type);
 
+bool ATTRIBUTE_MUST_USE os_is_cygwin_pty(int fd);
+
 Error ATTRIBUTE_MUST_USE os_self_exe_shared_libs(ZigList<Buf *> &paths);
 
 #endif

src/target.cpp

@@ -506,7 +506,7 @@ void get_native_target(ZigTarget *target) {
             &oformat);
     target->os = get_zig_os_type(os_type);
     target->is_native = true;
-    if (target->abi == ZigLLVM_UnknownEnvironment) {
+    if (target->os == OsWindows || target->abi == ZigLLVM_UnknownEnvironment) {
         target->abi = target_default_abi(target->arch, target->os);
     }
     if (target_is_glibc(target)) {
@@ -1504,6 +1504,16 @@ bool target_is_single_threaded(const ZigTarget *target) {
     return target_is_wasm(target);
 }
 
+static ZigLLVM_EnvironmentType target_get_win32_abi() {
+    FILE* files[] = { stdin, stdout, stderr, nullptr };
+    for (int i = 0; files[i] != nullptr; i++) {
+        if (os_is_cygwin_pty(_fileno(files[i]))) {
+            return ZigLLVM_GNU;
+        }
+    }
+    return ZigLLVM_MSVC;
+}
+
 ZigLLVM_EnvironmentType target_default_abi(ZigLLVM_ArchType arch, Os os) {
     if (arch == ZigLLVM_wasm32 || arch == ZigLLVM_wasm64) {
         return ZigLLVM_Musl;
@@ -1544,8 +1554,9 @@ ZigLLVM_EnvironmentType target_default_abi(ZigLLVM_ArchType arch, Os os) {
         case OsHurd:
             return ZigLLVM_GNU;
         case OsUefi:
-        case OsWindows:
             return ZigLLVM_MSVC;
+        case OsWindows:
+            return target_get_win32_abi();
         case OsLinux:
         case OsWASI:
             return ZigLLVM_Musl;