Fix mkpath() ignoring mode when umask is more restrictive

mkpath(dir, 0755) with umask 0027 silently creates a 0750 directory,
since mkdir(2) applies the umask to the requested mode.  Callers pass
an explicit mode and expect exactly that.

Apply the mode with chmod() after each successful mkdir().

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

ChangeLog.md

@@ -4,6 +4,14 @@ Change Log
 All notable changes to the project are documented in this file.
 
 
+[UNRELEASED][]
+--------------
+
+### Fixes
+- Fix `mkpath()`, and `fmkpath()`, not applying the given mode when the
+  process umask is more restrictive, e.g., requesting 0755 with umask
+  0027 silently created a 0750 directory
+
 [v2.6.2][] - 2025-11-22
 -----------------------