added a #include which was missing

Theodosius/Theodosius.sln

@@ -3,7 +3,7 @@ Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio Version 16
 VisualStudioVersion = 16.0.30907.101
 MinimumVisualStudioVersion = 10.0.40219.1
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "Theodosius", "Theodosius\Theodosius.vcxproj", "{BE437FEC-EA25-4E93-9B73-A028F9DD698F}"
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "Theodosius", "Theodosius.vcxproj", "{BE437FEC-EA25-4E93-9B73-A028F9DD698F}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution

includes/theo.h

@@ -2,6 +2,7 @@
 #include <Windows.h>
 #include <string>
 #include <vector>
+#include <functional>
 #include <map>
 
 namespace obfuscation{ class obfuscate; }