diff --git a/dll/win32/crypt32/crypt32_private.h b/dll/win32/crypt32/crypt32_private.h
index ac70fe04f82..838d76a91a9 100644
--- a/dll/win32/crypt32/crypt32_private.h
+++ b/dll/win32/crypt32/crypt32_private.h
@@ -152,7 +152,7 @@ BOOL WINAPI CRYPT_AsnEncodePubKeyInfoNoNull(DWORD dwCertEncodingType,
  */
 HCRYPTPROV WINAPI I_CryptGetDefaultCryptProv(ALG_ID);
 
-HINSTANCE hInstance DECLSPEC_HIDDEN;
+extern HINSTANCE hInstance DECLSPEC_HIDDEN;
 
 void crypt_oid_init(void) DECLSPEC_HIDDEN;
 void crypt_oid_free(void) DECLSPEC_HIDDEN;