linux-user: don't crash with null name

From Thayne Harbaugh.

path() may be called with null string, don't bother trying to
remap in that case.

Signed-off-by: Riku Voipio <riku.voipio@iki.fi>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6480 c046a42c-6fe2-441c-8c8c-71466251a162

linux-user/path.c

@@ -152,7 +152,7 @@ const char *path(const char *name)
 {
     /* Only do absolute paths: quick and dirty, but should mostly be OK.
        Could do relative by tracking cwd. */
-    if (!base || name[0] != '/')
+    if (!base || !name || name[0] != '/')
 	return name;
 
     return follow_path(base, name) ?: name;