yara: add dotnet module

Dotnet module added as a compile time option.
The dotnet module allows you to create more fine-grained rules
for .NET files by using attributes and features of the .NET file format.
http://yara.readthedocs.io/en/latest/modules/dotnet.html

Signed-off-by: Ashkan Jazayeri <ashkan@jazayeri.net>

utils/yara/Config.in

@@ -12,5 +12,12 @@ if PACKAGE_yara
 		default n
 		help
 		  Create rules based on behavioral info generated by a Cuckoo sandbox
+
+	config YARA_module_dotnet
+		bool "Dotnet module"
+		default n
+		help
+		  The dotnet module allows you to create more fine-grained rules
+		  for .NET files by using attributes and features of the .NET file format
 endif
 

utils/yara/Makefile

@@ -41,7 +41,7 @@ define Package/yara/description
 endef
 
 CONFIGURE_ARGS += \
-	--disable-dotnet \
+	$(if $(CONFIG_YARA_module_dotnet),--enable,--disable)-dotnet \
 	$(if $(CONFIG_YARA_module_magic),--enable,--disable)-magic \
 	$(if $(CONFIG_YARA_module_cuckoo),--enable,--disable)-cuckoo