diff --git a/Makefile.in b/Makefile.in
index 44451c8b8c..c09276bee6 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -1,5 +1,5 @@
 #
-# This file was automatically generated by tmake at 00:09, 2000/01/14
+# This file was automatically generated by tmake at 01:34, 2000/01/14
 # DO NOT CHANGE THIS FILE, YOUR CHANGES WILL BE LOST! CHANGE UNX.T!
 
 #
@@ -47,7 +47,10 @@ VP9 = @top_srcdir@/src/tiff
 VP10 = @top_srcdir@/src/zlib
 VP11 = @top_srcdir@/src/iodbc
 
-VPATH = $(VP1)@PATH_IFS@$(VP2)@PATH_IFS@$(VP3)@PATH_IFS@$(VP4)@PATH_IFS@$(VP5)@PATH_IFS@$(VP6)@PATH_IFS@$(VP7)@PATH_IFS@$(VP8)@PATH_IFS@$(VP9)@PATH_IFS@$(VP10)@PATH_IFS@$(VP11)
+# the comment at the end of the next line is needed because otherwise autoconf
+# would remove this line completely - it contains a built-in hack to remove
+# any VPATH assignment not containing ':'
+VPATH = $(VP1)@PATH_IFS@$(VP2)@PATH_IFS@$(VP3)@PATH_IFS@$(VP4)@PATH_IFS@$(VP5)@PATH_IFS@$(VP6)@PATH_IFS@$(VP7)@PATH_IFS@$(VP8)@PATH_IFS@$(VP9)@PATH_IFS@$(VP10)@PATH_IFS@$(VP11) # ':' for autoconf
 
 top_srcdir = @top_srcdir@
 prefix = @prefix@
diff --git a/distrib/msw/tmake/unx.t b/distrib/msw/tmake/unx.t
index 0e9c22bda0..32262da7bd 100644
--- a/distrib/msw/tmake/unx.t
+++ b/distrib/msw/tmake/unx.t
@@ -256,7 +256,10 @@ VP9 = @top_srcdir@/src/tiff
 VP10 = @top_srcdir@/src/zlib
 VP11 = @top_srcdir@/src/iodbc
 
-VPATH = $(VP1)@PATH_IFS@$(VP2)@PATH_IFS@$(VP3)@PATH_IFS@$(VP4)@PATH_IFS@$(VP5)@PATH_IFS@$(VP6)@PATH_IFS@$(VP7)@PATH_IFS@$(VP8)@PATH_IFS@$(VP9)@PATH_IFS@$(VP10)@PATH_IFS@$(VP11)
+# the comment at the end of the next line is needed because otherwise autoconf
+# would remove this line completely - it contains a built-in hack to remove
+# any VPATH assignment not containing ':'
+VPATH = $(VP1)@PATH_IFS@$(VP2)@PATH_IFS@$(VP3)@PATH_IFS@$(VP4)@PATH_IFS@$(VP5)@PATH_IFS@$(VP6)@PATH_IFS@$(VP7)@PATH_IFS@$(VP8)@PATH_IFS@$(VP9)@PATH_IFS@$(VP10)@PATH_IFS@$(VP11) # ':' for autoconf
 
 top_srcdir = @top_srcdir@
 prefix = @prefix@