yara: add enableStatic mode

useful because tests can be enabled in this mode

pkgs/tools/security/yara/default.nix

@@ -10,6 +10,7 @@
 , enableDotNet ? true
 , enableMacho ? true
 , enableMagic ? true, file
+, enableStatic ? false
 }:
 
 stdenv.mkDerivation rec {
@@ -40,8 +41,11 @@ stdenv.mkDerivation rec {
     (lib.enableFeature enableDotNet "dotnet")
     (lib.enableFeature enableMacho "macho")
     (lib.enableFeature enableMagic "magic")
+    (lib.enableFeature enableStatic "static")
   ];
 
+  doCheck = enableStatic;
+
   meta = with lib; {
     description = "The pattern matching swiss knife for malware researchers";
     homepage = "http://Virustotal.github.io/yara/";