interface: fix the substring search

libsolidity/interface/Exceptions.cpp

@@ -56,3 +56,10 @@ Error::Error(Type _type): m_type(_type)
 		break;
 	}
 }
+
+bool Error::searchForSubstring(const std::string& _substr) const
+{
+	if (const std::string* str = boost::get_error_info<errinfo_comment>(*this))
+		return str->find(_substr) != std::string::npos;
+	return _substr.empty();
+}

libsolidity/interface/Exceptions.h

@@ -23,7 +23,6 @@
 #pragma once
 
 #include <string>
-#include <regex>
 #include <utility>
 #include <libdevcore/Exceptions.h>
 #include <libevmasm/SourceLocation.h>
@@ -58,13 +57,7 @@ public:
 
 	Type type() const { return m_type; }
 	std::string const& typeName() const { return m_typeName; }
-	bool regex_search(const std::string& _reg) const
-	{
-		if (std::string const* str = boost::get_error_info<errinfo_comment>(*this))
-			return std::regex_search(*str, std::regex(_reg));
-		else
-			return false;
-	}
+	bool searchForSubstring(const std::string& _substr) const;
 
 	/// helper functions
 	static Error const* containsErrorOfType(ErrorList const& _list, Error::Type _type)