Use g_strerror() instead of strerror() - we want UTF-8.

Use g_strerror() instead of strerror() - we want UTF-8.

Original commit message from CVS:
* gst/gstplugin.c: (gst_plugin_load_file):
* plugins/elements/gstfilesrc.c: (gst_mmap_buffer_finalize),
(gst_file_src_map_region), (gst_file_src_start):
* plugins/indexers/gstfileindex.c: (gst_file_index_load),
(gst_file_index_commit):
Use g_strerror() instead of strerror() - we want UTF-8.