diff --git a/src/ar65/library.c b/src/ar65/library.c
index 342bc25d3..d12fb198a 100644
--- a/src/ar65/library.c
+++ b/src/ar65/library.c
@@ -37,10 +37,10 @@
 #include <string.h>
 #include <errno.h>
 #if defined(_WIN32)
-#include <process.h>
+#  include <process.h>
 #else
-#include <sys/types.h>
-#include <unistd.h>
+#  include <sys/types.h>
+#  include <unistd.h>
 #endif
 
 /* common */