Use std::filesystem in favor of custom module

Reuse some code.  Fix a bug in the process.

Resolves openbmc/openbmc#1254

Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
Change-Id: I3fdbb70d6372f4a3193204bd2c9b6535315a3c70
diff --git a/configure.ac b/configure.ac
index b717976..f08030e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -23,6 +23,7 @@
 
 # Checks for header files.
 AC_CHECK_HEADER(sdbusplus/server.hpp, ,[AC_MSG_ERROR([Could not find sdbusplus/server.hpp...sdbusplus developement package required])])
+AC_CHECK_HEADER(experimental/filesystem, ,[AC_MSG_ERROR([Could not find experimental/filesystem...libstdc++fs developement package required])])
 
 # Checks for library functions.
 LT_INIT