diff --git a/src-self-hosted/clang.zig b/src-self-hosted/clang.zig
index db76185ab9b9d5fbe1ef7fd0610d7f4f249b5593..f2433ae60cdf47e48d132c13151103134df03117 100644
--- a/src-self-hosted/clang.zig
+++ b/src-self-hosted/clang.zig
@@ -940,7 +940,7 @@ pub const struct_ZigClangExprEvalResult = extern struct {
 
 pub const struct_ZigClangAPValue = extern struct {
     Kind: ZigClangAPValue_ValueKind,
-    Data: if (builtin.os == .windows) [52]u8 else [68]u8,
+    Data: if (builtin.os == .windows and builtin.abi == .msvc) [52]u8 else [68]u8,
 };
 
 pub const ZigClangAPValue_ValueKind = extern enum {
diff --git a/src/zig_clang.h b/src/zig_clang.h
index 183aaef68166f2aee48cbe466e6bdd373b63ada1..9d03b592fdae2fdead366d6af8cdfb54edfa7ba8 100644
--- a/src/zig_clang.h
+++ b/src/zig_clang.h
@@ -48,7 +48,7 @@ enum ZigClangAPValue_ValueKind {
 struct ZigClangAPValue {
     enum ZigClangAPValue_ValueKind Kind;
     // experimentally-derived size of clang::APValue::DataType
-#ifdef _WIN32
+#if defined(WIN32) && defined(_MSC_VER)
     char Data[52];
 #else
     char Data[68];