that interrupted system calls are automatically restarted, and we minimize
hassles with handling EINTR (in particular as EINTR handling is pretty broken
on Linux).
+
+- When applying C-style unescaping as well as specifier expansion on the same
+ string, always apply the C-style unescaping fist, followed by the specifier
+ expansion. When doing the reverse, make sure to escape '%' in specifier-style
+ first (i.e. '%' → '%%'), and then do C-style escaping where necessary.