Support equals sign in XPath expressions

test/test-cases/regression/variable-XML.json

@@ -0,0 +1,46 @@
+[
+  {
+    "enabled":1,
+    "version_min":300000,
+    "title":"Testing XPath expression with equals sign",
+    "expected":{
+      "http_code": 403
+    },
+    "client":{
+      "ip":"200.249.12.31",
+      "port":123
+    },
+    "request":{
+      "headers":{
+        "Host":"localhost",
+        "User-Agent":"curl/7.38.0",
+        "Accept":"*/*",
+        "Content-Type": "text/xml"
+      },
+      "uri":"/?key=value&key=other_value",
+      "method":"POST",
+      "body": [
+        "<?xml version=\"1.0\" encoding=\"UTF-8\"?>",
+        "<!DOCTYPE author [",
+        "<!ELEMENT book ANY>",
+        "<!ENTITY js SYSTEM \"/etc/passwd\">",
+        "]>",
+        "<bookstore>",
+        "<some-tag>aaa</some-tag><some-tag>bbb</some-tag>",
+        "</bookstore>"
+      ]
+
+    },
+    "server":{
+      "ip":"200.249.12.31",
+      "port":80
+    },
+    "rules":[
+        "SecRuleEngine On",
+        "SecRequestBodyAccess On",
+        "SecRule REQUEST_HEADERS:Content-Type \"^text/xml$\" \"id:500011,phase:1,t:none,t:lowercase,nolog,pass,ctl:requestBodyProcessor=XML\"",
+        "SecRule XML://bookstore/*[local-name()='some-tag'] \"bbb\" \"id:500012,phase:3,t:none,t:lowercase,log,deny,status:403\""
+    ]
+  }
+]
+