diff --git a/src/bin/bash/config.h b/src/bin/bash/config.h
index 21c460b3e9..29ff8984e7 100644
--- a/src/bin/bash/config.h
+++ b/src/bin/bash/config.h
@@ -419,7 +419,9 @@
 
 /* #undef HAVE_STD_PUTENV */
 
+#if __HAIKU__
 #define HAVE_STD_UNSETENV 1
+#endif
 
 /* #undef HAVE_PRINTF_A_FORMAT */