Add more error handling to bp2::ext cwd.ipp. (#354)

* Add more error handling to bp2::ext cwd.ipp.

* Remove redundant errno checks

these functions don't fail...

include/boost/process/v2/ext/impl/cwd.ipp

@@ -125,7 +125,6 @@ filesystem::path cwd(boost::process::v2::pid_type pid, boost::system::error_code
 
 #elif defined(__FreeBSD__)
 
-// FIXME: Add error handling.
 filesystem::path cwd(boost::process::v2::pid_type pid, boost::system::error_code & ec) 
 {
     filesystem::path path;
@@ -139,9 +138,7 @@ filesystem::path cwd(boost::process::v2::pid_type pid, boost::system::error_code
                 filestat *fst = nullptr;
                 STAILQ_FOREACH(fst, head, next) {
                     if (fst->fs_uflags & PS_FST_UFLAG_CDIR) 
-                    {
                         path = filesystem::canonical(fst->fs_path, ec);
-                    }
                 }
                 procstat_freefiles(proc_stat, head);
             }
@@ -160,7 +157,6 @@ filesystem::path cwd(boost::process::v2::pid_type pid, boost::system::error_code
 
 #elif defined(__DragonFly__)
 
-// FIXME: Add error handling.
 filesystem::path cwd(boost::process::v2::pid_type pid, boost::system::error_code & ec) 
 {
     filesystem::path path;
@@ -185,7 +181,8 @@ filesystem::path cwd(boost::process::v2::pid_type pid, boost::system::error_code
         }
         else
             BOOST_PROCESS_V2_ASSIGN_LAST_ERROR(ec)
-        pclose(fp);
+        if (pclose(fp) == -1)
+            BOOST_PROCESS_V2_ASSIGN_LAST_ERROR(ec)
     }
     else
         BOOST_PROCESS_V2_ASSIGN_LAST_ERROR(ec)