contrib: create static library for elfparser

I want to move a bunch of this "contrib" style sources into their own
area so we can statically link them but keep them separate from main
sysprof code.

contrib/elfparser/demangle.cpp

@@ -0,0 +1,40 @@
+/* demangle.cpp
+ *
+ * Copyright (C) 2016 Christian Hergert <chergert@redhat.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <cxxabi.h>
+#include <stdlib.h>
+
+#include "demangle.h"
+
+gchar *
+sysprof_cplus_demangle (const gchar *name)
+{
+  char *real_name;
+  gchar *ret;
+  int status;
+
+  real_name = abi::__cxa_demangle (name, 0, 0, &status);
+
+  if (real_name == NULL)
+    return NULL;
+
+  ret = g_strdup (real_name);
+  free (real_name);
+
+  return ret;
+}