diff --git a/pkgs/by-name/cn/cnijfilter2/package.nix b/pkgs/by-name/cn/cnijfilter2/package.nix
index c040987773cd0..b3a2e4f8afa67 100644
--- a/pkgs/by-name/cn/cnijfilter2/package.nix
+++ b/pkgs/by-name/cn/cnijfilter2/package.nix
@@ -36,6 +36,7 @@ stdenv.mkDerivation {
 
   patches = [
     ./patches/get_protocol.patch
+    ./patches/add_missing_import.patch
   ];
 
   # lgmon3's --enable-libdir flag is used soley for specifying in which
diff --git a/pkgs/by-name/cn/cnijfilter2/patches/add_missing_import.patch b/pkgs/by-name/cn/cnijfilter2/patches/add_missing_import.patch
new file mode 100644
index 0000000000000..298416e27706f
--- /dev/null
+++ b/pkgs/by-name/cn/cnijfilter2/patches/add_missing_import.patch
@@ -0,0 +1,12 @@
+diff --git a/lgmon3/src/keytext.c b/lgmon3/src/keytext.c
+index 8c15ff8..b80bbe5 100644
+--- a/lgmon3/src/keytext.c
++++ b/lgmon3/src/keytext.c
+@@ -37,6 +37,7 @@
+ #include <unistd.h>
+ #include <libxml/parser.h>	/* Ver.2.80 */
+ #include <string.h>
++#include <stdlib.h>
+ 
+ #include "keytext.h"
+