--- a/lib/Makefile.in
+++ b/lib/Makefile.in
@@ -205,7 +205,7 @@
 MAINTAINERCLEANFILES = $(BUILT_SOURCES)
 DISTCLEANFILES = lstat.c stat.c unlocked-io.h
 
-EXTRA_DIST = xstat.in config.charset ref-add.sin ref-del.sin unlocked-io.hin
+EXTRA_DIST = xstat.in config.charset ref-add.sin ref-del.sin gen-uio
 
 charset_alias = $(DESTDIR)$(libdir)/charset.alias
 charset_tmp = $(DESTDIR)$(libdir)/charset.tmp
@@ -221,9 +221,6 @@
   clearerr feof ferror fflush fgets fputc fputs \
   fread fwrite getc getchar putc putchar
 
-
-a_z = abcdefghijklmnopqrstuvwxyz
-A_Z = ABCDEFGHIJKLMNOPQRSTUVWXYZ
 subdir = lib
 mkinstalldirs = $(SHELL) $(top_srcdir)/mkinstalldirs
 CONFIG_HEADER = $(top_builddir)/config.h
@@ -1002,19 +999,8 @@
 	sed -e '/^#/d' -e 's/@''PACKAGE''@/@PACKAGE@/g' $< > $@-t
 	mv $@-t $@
 
-unlocked-io.h: $(srcdir)/unlocked-io.hin Makefile.am
-	tmp=t$$$$;							\
-	for f in $(io_functions); do					\
-	  u=`echo $$f|tr $(a_z) $(A_Z)`;				\
-	  echo "#  if HAVE_$${u}_UNLOCKED"		;		\
-	  echo "#   undef $$f"				;		\
-	  echo "#   define $$f(S) $${f}_unlocked (S)"	;		\
-	  echo '#  endif'				;		\
-	done > $$tmp;							\
-	sed '/^@replace_this@$$/r '$$tmp $(srcdir)/unlocked-io.hin	\
-	  | sed '/^@replace_this@$$/d'					\
-	  > $@t;							\
-	rm -f $$tmp;							\
+unlocked-io.h: $(srcdir)/gen-uio Makefile.am
+	srcdir=$(srcdir) $(SHELL) $(srcdir)/gen-uio $(io_functions) > $@t
 	mv $@t $@
 # Tell versions [3.59,3.63) of GNU make to not export all variables.
 # Otherwise a system limit (for SysV at least) may be exceeded.