Change 'ensure-directories-exist' to look for 'mkdir' in $PATH, not in /bin.

--- maxima-5.36.1/lisp-utils/defsystem.lisp.orig	2014-11-22 16:21:30.000000000 -0500
+++ maxima-5.36.1/lisp-utils/defsystem.lisp	2015-05-25 21:53:31.223648483 -0400
@@ -4627,7 +4627,7 @@
         (cmd (if (member :win32 *features*)
                  (format nil "mkdir \"~a\""
                          (coerce (subst #\\ #\/ (coerce (namestring dir) 'list)) 'string))
-                 (format nil "/bin/mkdir -p ~S" (namestring dir)))))
+                 (format nil "mkdir -p ~S" (namestring dir)))))
    (unless (directory dir)
      (lisp:system cmd))
    ;; The second return value is supposed to be T if directories were
ange='this.form.submit();'>
<option value='koszko' selected='selected'>koszko</option>
<option value='koszko-scripts'>koszko-scripts</option>
</select> <input type='submit' value='switch'/></form></td></tr>
<tr><td class='sub'>Wojtek's customized Guix</td><td class='sub right'></td></tr></table>
<table class='tabs'><tr><td>
<a href='/guix/about/'>about</a><a href='/guix/'>summary</a><a href='/guix/refs/?id=6483ae57a524e3c6469286b75150e96b79f11543'>refs</a><a class='active' href='/guix/log/gnu/services/kerberos.scm'>log</a><a href='/guix/tree/gnu/services/kerberos.scm?id=6483ae57a524e3c6469286b75150e96b79f11543'>tree</a><a href='/guix/commit/gnu/services/kerberos.scm?id=6483ae57a524e3c6469286b75150e96b79f11543'>commit</a><a href='/guix/diff/gnu/services/kerberos.scm?id=6483ae57a524e3c6469286b75150e96b79f11543'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/services/kerberos.scm'>
<input type='hidden' name='id' value='6483ae57a524e3c6469286b75150e96b79f11543'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=6483ae57a524e3c6469286b75150e96b79f11543'>root</a>/<a href='/guix/log/gnu?id=6483ae57a524e3c6469286b75150e96b79f11543'>gnu</a>/<a href='/guix/log/gnu/services?id=6483ae57a524e3c6469286b75150e96b79f11543'>services</a>/<a href='/guix/log/gnu/services/kerberos.scm?id=6483ae57a524e3c6469286b75150e96b79f11543'>kerberos.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/services/kerberos.scm?id=6483ae57a524e3c6469286b75150e96b79f11543&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>