diff --git a/build_patches/011-missing_unistd.patch b/build_patches/011-missing_unistd.patch
new file mode 100644
index 0000000..da696c4
--- /dev/null
+++ b/build_patches/011-missing_unistd.patch
@@ -0,0 +1,12 @@
+Index: src/mklibs-readelf/elf.cpp
+===================================================================
+--- a/src/mklibs-readelf/elf.cpp
++++ b/src/mklibs-readelf/elf.cpp
+@@ -25,6 +25,7 @@
+ #include <fcntl.h>
+ #include <sys/mman.h>
+ #include <sys/stat.h>
++#include <unistd.h>
+ 
+ using namespace Elf;
+ 
diff --git a/build_script.sh b/build_script.sh
index 6dd2a06..1c69a9f 100755
--- a/build_script.sh
+++ b/build_script.sh
@@ -15,6 +15,9 @@ prepare() {
 	#Upgrade batman advanced to version 2012.2.0
 	svn update --revision=32386 ./build_dir/feeds/packages/net/batman-adv/
 
+	#fix mktools build error on arch linux
+	cp ./build_patches/011-missing_unistd.patch ./build_dir/tools/mklibs/patches/
+
 	# fix some tinc mem leaks
 	mkdir ./build_dir/feeds/packages/net/tinc/patches
 	cp ./build_patches/tinc/001_fix_a_few_small_memory_leaks.patch ./build_dir/feeds/packages/net/tinc/patches/001_fix_a_few_small_memory_leaks.patch