Rename regex.h and regex.cpp to regex_yaml, so they don't interfere with the posix variant

src/exp.h

@@ -7,7 +7,7 @@
 #pragma once
 #endif
 
-#include "regex.h"
+#include "regex_yaml.h"
 #include <string>
 #include <ios>
 #include "stream.h"

src/regex.cpp → src/regex_yaml.cpp

-#include "regex.h"
+#include "regex_yaml.h"
 
 namespace YAML {
 // constructors

src/scanscalar.h

@@ -8,7 +8,7 @@
 #endif
 
 #include <string>
-#include "regex.h"
+#include "regex_yaml.h"
 #include "stream.h"
 
 namespace YAML {

src/scantag.cpp

 #include "scanner.h"
-#include "regex.h"
+#include "regex_yaml.h"
 #include "exp.h"
 #include "yaml-cpp/exceptions.h"