--- a/src/interp.c
+++ b/src/interp.c
@@ -1540,6 +1540,10 @@
     return;
 }
 
+#ifdef USELOCALE
+#include <locale.h>
+#include <langinfo.h>
+#endif
 
 /**
  * \brief slet()
@@ -1609,8 +1613,6 @@
             // reconvert numeric value based on locale's D_FMT format instead of current format
             char * f = &v->format[1];
             #ifdef USELOCALE
-            #include <locale.h>
-            #include <langinfo.h>
             char * loc = NULL;
             f = NULL;
             loc = setlocale(LC_TIME, "");