2005-08-26  Stepan Kasal  <address@hidden>

	* lib/m4sugar/m4sh.m4 (_AS_VERSION_COMPARE_PREPARE): Fix the awk script
	so that it works with /usr/xpg4/bin/awk on Solaris 8 (and newer?).

Index: lib/m4sugar/m4sh.m4
===================================================================
RCS file: /cvsroot/autoconf/autoconf/lib/m4sugar/m4sh.m4,v
retrieving revision 1.149
diff -u -r1.149 m4sh.m4
--- lib/m4sugar/m4sh.m4	25 Aug 2005 21:29:54 -0000	1.149
+++ lib/m4sugar/m4sh.m4	26 Aug 2005 15:32:03 -0000
@@ -1026,9 +1026,12 @@
 # ---------------------------
 # Output variables for comparing version numbers.
 m4_defun([_AS_VERSION_COMPARE_PREPARE],
-[[as_awk_strverscmp='
+[[
   # Use only awk features that work with 7th edition Unix awk (1978).
   # My, what an old awk you have, Mr. Solaris!
+  # Moreover, avoid comparisons with empty strings, because of the bug
+  # in Solaris' /usr/xpg4/bin/awk.  (See the manual for details.)
+  as_awk_strverscmp='
   END {
     while (length(v1) || length(v2)) {
       # Set d1 to be the next thing to compare from v1, and likewise for d2.
@@ -1074,8 +1077,14 @@
 	}
       } else {
 	# The normal case, without worrying about digits.
-	if (length(v1)) { d1 = substr(v1, 1, 1); v1 = substr(v1,2) } else d1=v1
-	if (length(v2)) { d2 = substr(v2, 1, 1); v2 = substr(v2,2) } else d2=v2
+
+	# Treat empty string here, to avoiding problems with
+	# /usr/xpg4/bin/awk on Solaris.
+	if (length(v1) == 0) exit 1
+	if (length(v2) == 0) exit 2
+
+	d1 = substr(v1, 1, 1); v1 = substr(v1,2)
+	d2 = substr(v2, 1, 1); v2 = substr(v2,2)
       }
       if (d1 < d2) exit 1
       if (d1 > d2) exit 2