diff --git a/src/magic.c b/src/magic.c
index 6d713ba63..943c59db2 100644
--- a/src/magic.c
+++ b/src/magic.c
@@ -76,6 +76,7 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #include <stdlib.h>
 #include <limits.h>
 #include <assert.h>
+#include <errno.h>
 #include <math.h>
 
 const char *magic_school[MAXMAGIETYP] = {