introspection: Skip g_mkdtemp() and friends

Based on bugs [1] and [2], gobject-introspection does not handle the
same string being 1) returned from an inout argument and 2) returned
as the function's return value, and is not going to.
Therefore, these functions should be skipped in introspection.

[1] https://bugzilla.gnome.org/show_bug.cgi?id=679351
[2] https://bugzilla.gnome.org/show_bug.cgi?id=679362

https://bugzilla.gnome.org/show_bug.cgi?id=777493

glib/gfileutils.c

@@ -1349,7 +1349,7 @@ wrap_g_open (const gchar *filename,
 }
 
 /**
- * g_mkdtemp_full:
+ * g_mkdtemp_full: (skip)
  * @tmpl: (type filename): template directory name
  * @mode: permissions to create the temporary directory with
  *
@@ -1382,7 +1382,7 @@ g_mkdtemp_full (gchar *tmpl,
 }
 
 /**
- * g_mkdtemp:
+ * g_mkdtemp: (skip)
  * @tmpl: (type filename): template directory name
  *
  * Creates a temporary directory. See the mkdtemp() documentation
@@ -1410,7 +1410,7 @@ g_mkdtemp (gchar *tmpl)
 }
 
 /**
- * g_mkstemp_full:
+ * g_mkstemp_full: (skip)
  * @tmpl: (type filename): template filename
  * @flags: flags to pass to an open() call in addition to O_EXCL
  *     and O_CREAT, which are passed automatically
@@ -1446,7 +1446,7 @@ g_mkstemp_full (gchar *tmpl,
 }
 
 /**
- * g_mkstemp:
+ * g_mkstemp: (skip)
  * @tmpl: (type filename): template filename
  *
  * Opens a temporary file. See the mkstemp() documentation