[UCRT] Import Microsoft.Windows.SDK.CRTSource version 10.0.22621.3

Imported from https://www.nuget.org/packages/Microsoft.Windows.SDK.CRTSource/10.0.22621.3
License: MIT

sdk/lib/ucrt/internal/SetEnvironmentVariableA.cpp

@@ -0,0 +1,40 @@
+//
+// SetEnvironmentVariableA.cpp
+//
+//      Copyright (c) Microsoft Corporation. All rights reserved.
+//
+// Definition of __acrt_SetEnvironmentVariableA.
+//
+
+#include <corecrt_internal_win32_buffer.h>
+
+BOOL __cdecl __acrt_SetEnvironmentVariableA(
+    LPCSTR const lpName,
+    LPCSTR const lpValue
+    )
+{
+    __crt_internal_win32_buffer<wchar_t> wide_name;
+    __crt_internal_win32_buffer<wchar_t> wide_value;
+
+    errno_t const cvt1 = __acrt_mbs_to_wcs_cp(
+        lpName,
+        wide_name,
+        __acrt_get_utf8_acp_compatibility_codepage()
+        );
+
+    if (cvt1 != 0) {
+        return FALSE;
+    }
+
+    errno_t const cvt2 = __acrt_mbs_to_wcs_cp(
+        lpValue,
+        wide_value,
+        __acrt_get_utf8_acp_compatibility_codepage()
+        );
+
+    if (cvt2 != 0) {
+        return FALSE;
+    }
+
+    return ::SetEnvironmentVariableW(wide_name.data(), wide_value.data());
+}