Patch for autoconf/145

[Pavel Roskin]

Hello!

Currently config.status removes VPATH from the makefiles for the srcdir
builds. The exception is made for the values containing a colon.

What are the problems with this approach:

1) The line numbers are shifted. An error at line 341 in Makefile would
correspond to the line 340 in Makefile.in.

2) Backslashes at the end of line are not taken into account, i.e. the
lines are not unfolded. Colons on the subsequent lines are not detected.

3) Expressions like "address@hidden@" are removed. Autoconf should not
remove user input without warnings, even if it's unportable.

ChangeLog:
        * acgeneral.m4 (AC_OUTPUT): Remove VPATH only if it's set exactly
        to @address@hidden Leave an empty line when VPATH is removed.

_______________________________
--- acgeneral.m4
+++ acgeneral.m4
@@ -3501,10 +3501,9 @@
 # Let make expand exec_prefix.
 test "x$exec_prefix" = xNONE && exec_prefix='${prefix}'

-# VPATH is dangerous, but if there is a colon in the path, we need to
-# keep it.
+# VPATH is dangerous, so comment remove it if it's just @address@hidden
 if test "x$srcdir" = x.; then
-  ac_vpsub=['/^[       ]*VPATH[        ]*=[^:]*$/d']
+  ac_vpsub=['s/^[      ]*VPATH[        ]*=[    address@hidden@[        ]*$//']
 fi

 m4_ifset([AC_LIST_HEADERS], [DEFS=-DHAVE_CONFIG_H], [AC_OUTPUT_MAKE_DEFS()])
_______________________________

Regards,
Pavel Roskin