Include RE2 library

third_party/re2/testinstall.cc

+#include <re2/re2.h>
+#include <re2/filtered_re2.h>
+#include <stdio.h>
+
+using namespace re2;
+
+int main(void) {
+        FilteredRE2 f;
+        int id;
+        f.Add("a.*b.*c", RE2::DefaultOptions, &id);
+        vector<string> v;
+        f.Compile(&v);
+
+        if(RE2::FullMatch("axbyc", "a.*b.*c")) {
+                printf("PASS\n");
+                return 0;
+        }
+        printf("FAIL\n");
+        return 2;
+}