Ignore non-absolute $HOME when started from native process

* uinfo.cc (cygheap_user::ontherange): Ignore $HOME if it's not
	starting with a slash (aka, absolute POSIX Path).

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

winsup/cygwin/ChangeLog

@@ -1,3 +1,8 @@
+2015-07-23  Corinna Vinschen  <corinna@vinschen.de>
+
+	* uinfo.cc (cygheap_user::ontherange): Ignore $HOME if it's not
+	starting with a slash (aka, absolute POSIX Path).
+
 2015-07-21  Corinna Vinschen  <corinna@vinschen.de>
 
 	* common.din (siglongjmp): Export.

winsup/cygwin/release/2.2.0

@@ -11,6 +11,9 @@ What's new:
 What changed:
 -------------
 
+- When started from a non-Cygwin process, check if $HOME starts with a
+  slash (absolute POSIX path).  Otherwise ignore it.
+
 
 Bug Fixes
 ---------

winsup/cygwin/uinfo.cc

@@ -331,8 +331,15 @@ cygheap_user::ontherange (homebodies what, struct passwd *pw)
       char *p;
 
       if ((p = getenv ("HOME")))
-	debug_printf ("HOME is already in the environment %s", p);
+	{
-      else
+	  debug_printf ("HOME is already in the environment %s", p);
+	  if (p[0] != '/')
+	    {
+	      p = NULL;
+	      debug_printf ("discard HOME, no absolute POSIX path");
+	    }
+	}
+      if (!p)
 	{
 	  if (pw && pw->pw_dir && *pw->pw_dir)
 	    {