change handling of standard input

For `-f /dev/stdin`, the `pathname` of the parsing context will be empty
as for any other streamed input.

`instance_t::include_directive` did not work as expected for `-f /dev/stdin`
and relative file names. One would expect them to be relative to the current
directory rather than `/dev`.

This will lead to `While parsing file ""` messages. This could be
adjusted to read `While parsing standard input`, but maybe it's not
worth the special cases.

This commit also fixes bug 788: behaviour of source_context for '-f -'

1 files changed, 2 insertions, 2 deletions

diff --git a/src/item.cc b/src/item.cc
index 362fac7f..4e2a487c 100644
--- a/src/item.cc
+++ b/src/item.cc
@@ -582,8 +582,8 @@ string item_context(const item_t& item, const string& desc)
 
   std::ostringstream out;
 
-  if (item.pos->pathname == path("/dev/stdin")) {
-    out << desc << _(" from standard input:");
+  if (item.pos->pathname.empty()) {
+    out << desc << _(" from streamed input:");
     return out.str();
   }