Fix multiple-including.

lib/auth.h

@@ -1,3 +1,4 @@
+#pragma once
 #include <string>
 #include <openssl/rsa.h>
 #include <openssl/x509.h>

lib/base64.h

@@ -1,3 +1,4 @@
+#pragma once
 #include <string>
 
 /// Holds base64 decoding and encoding functions.

lib/config.h

@@ -1,6 +1,7 @@
 /// \file config.h
 /// Contains generic function headers for managing configuration.
 
+#pragma once
 #include <string>
 
 #define STRINGIFY(x) #x

lib/json.h

@@ -1,5 +1,6 @@
 /// \file json.h Holds all JSON-related headers.
 
+#pragma once
 #include <string>
 #include <deque>
 #include <map>

lib/procs.h

@@ -1,6 +1,7 @@
 /// \file procs.h
 /// Contains generic function headers for managing processes.
 
+#pragma once
 #include <unistd.h>
 #include <string>
 #include <map>