include limits.h to fix build on BSD systems
diff --git a/src/afl-ld-lto.c b/src/afl-ld-lto.c
index 49c04e4..1fb0160 100644
--- a/src/afl-ld-lto.c
+++ b/src/afl-ld-lto.c
@@ -45,6 +45,11 @@
 
 #include <dirent.h>
 
+#if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) || \
+    defined(__DragonFly__)
+  #include <limits.h>
+#endif
+
 #ifdef __APPLE__
   #include <sys/syslimits.h>
 #endif