diff --git a/src/include/utils/pg_locale.h b/src/include/utils/pg_locale.h
index 931f5b3b880..2b072cafb4d 100644
--- a/src/include/utils/pg_locale.h
+++ b/src/include/utils/pg_locale.h
@@ -18,6 +18,8 @@
 /* only include the C APIs, to avoid errors in cpluspluscheck */
 #undef U_SHOW_CPLUSPLUS_API
 #define U_SHOW_CPLUSPLUS_API 0
+#undef U_SHOW_CPLUSPLUS_HEADER_API
+#define U_SHOW_CPLUSPLUS_HEADER_API 0
 #include <unicode/ucol.h>
 #endif