diff --git a/ChangeLog b/ChangeLog
index 799dd81d62..6c760de778 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue Aug  7 12:45:13 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* configure.in (ac_cv_func_isinf): set yes also on OpenSolaris.
+	  [ruby-Bugs-12859]
+
 Tue Aug  7 12:31:51 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* io.c (pipe_open): fix for win32 platforms.
diff --git a/configure.in b/configure.in
index dcccf18892..effadc38fb 100644
--- a/configure.in
+++ b/configure.in
@@ -486,10 +486,10 @@ bow)		ac_cv_func_setitimer=no
 		;;
 superux*)     ac_cv_func_setitimer=no
               ;;
-solaris*2.10)  if test -z "$GCC"; then
-                      ac_cv_func_isinf=yes
+solaris*2.1*) if test -z "$GCC"; then
+	           ac_cv_func_isinf=yes
               fi
-               LIBS="-lm $LIBS"
+              LIBS="-lm $LIBS"
               ;;
 *) LIBS="-lm $LIBS";;
 esac