* path.h (class path_conv): Convert path from char array to char *.

Initialize to NULL in constructors.  Drop normalized_path_size member.
	(path_conv::size): Remove.
	(path_conv::operator =): Always copy with sizeof path_conv.  Always
	duplicate path on cygheap.
	(path_conv::set_path): Move implementation to spawn.cc.
	* path.cc (path_conv::set_normalized_path): Always allocate
	normalized_path on cygheap.
	(path_conv::check): Don't work on path, rather allocate THIS_path in
	TLS and use it throughout.  When finished, allocate path on cygheap
	and copy over.  Defer tacking on extension after having copied path.
	* spawn.cc (path_conv::set_path): Implement here.

winsup/cygwin/spawn.cc

@@ -87,6 +87,14 @@ perhaps_suffix (const char *prog, path_conv& buf, int& err, unsigned opt)
   return ext;
 }
 
+inline void
+path_conv::set_path (const char *p)
+{
+  if (path)
+    cfree (path);
+  path = cstrdup (p);
+}
+
 /* Find an executable name, possibly by appending known executable
    suffixes to it.  The win32-translated name is placed in 'buf'.
    Any found suffix is returned in known_suffix.