ircd::fs: Save the std openmode in the fd::opts struct.

include/ircd/fs/fd.h

@@ -45,6 +45,9 @@ struct ircd::fs::fd
 
 struct ircd::fs::fd::opts
 {
+	/// std openmode passed from ctor.
+	std::ios::openmode mode {std::ios::openmode(0)};
+
 	/// open(2) flags. Usually generated from ios::open_mode ctor.
 	ulong flags {0};
 

ircd/fs.cc

@@ -652,7 +652,11 @@ ircd::fs::path_str(const string_view &s)
 //
 
 ircd::fs::fd::opts::opts(const std::ios::openmode &mode)
-:flags
+:mode
+{
+	mode
+}
+,flags
 {
 	posix_flags(mode)
 }