diff --git a/unix/mpconfigport.h b/unix/mpconfigport.h
index 4dbb8ee2e3..a6bd98a727 100644
--- a/unix/mpconfigport.h
+++ b/unix/mpconfigport.h
@@ -84,7 +84,9 @@
 #define MICROPY_PY_SYS_STDFILES     (1)
 #define MICROPY_PY_SYS_EXC_INFO     (1)
 #define MICROPY_PY_COLLECTIONS_ORDEREDDICT (1)
+#ifndef MICROPY_PY_MATH_SPECIAL_FUNCTIONS
 #define MICROPY_PY_MATH_SPECIAL_FUNCTIONS (1)
+#endif
 #define MICROPY_PY_CMATH            (1)
 #define MICROPY_PY_IO_FILEIO        (1)
 #define MICROPY_PY_GC_COLLECT_RETVAL (1)