FreeBSD gcc

Found

r1177492

r1177492 | danielsh | 2011-09-29 22:30:59 -0500 (Thu, 29 Sep 2011)

Silence a justified compiler warning.

Found by: FreeBSD gcc

* subversion/libsvn_subr/io.c
  (svn_io_detect_mimetype2): Declare PATH_EXT as a pointer to non-const char,
    and tweak casts accordingly.