diff --git a/ChangeLog b/ChangeLog
index d9367a1979..cfaea93003 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+Mon Oct 24 23:55:31 2011  Tanaka Akira  <akr@fsij.org>
+
+	* complex.c: use "__sun" instead of "__sun__" to detect SunOS.
+
+	* math.c: ditto.
+
+	* hash.c: ditto.
+
+	* atomic.h: ditto.
+
+	* ext/io/wait/wait.c: ditto.
+
+	[ruby-dev:44693]
+
 Mon Oct 24 22:45:37 2011  Tanaka Akira  <akr@fsij.org>
 
 	* io.c: use "__sun" instead of "sun" to detect SunOS.
diff --git a/atomic.h b/atomic.h
index 6dbad6db2d..d314804a15 100644
--- a/atomic.h
+++ b/atomic.h
@@ -42,7 +42,7 @@ typedef unsigned int rb_atomic_t; /* Anything OK */
 # define ATOMIC_OR(var, val) __sync_or_and_fetch(&(var), (val))
 # define ATOMIC_EXCHANGE(var, val) __sync_lock_test_and_set(&(var), (val))
 
-#elif defined(__sun) || defined(__sun__)
+#elif defined(__sun)
 #include <atomic.h>
 typedef unsigned int rb_atomic_t;
 
diff --git a/complex.c b/complex.c
index fd0088c574..3186e62fc8 100644
--- a/complex.c
+++ b/complex.c
@@ -1173,7 +1173,7 @@ nucomp_eql_p(VALUE self, VALUE other)
 inline static VALUE
 f_signbit(VALUE x)
 {
-#if defined(HAVE_SIGNBIT) && defined(__GNUC__) && defined(__sun__) && \
+#if defined(HAVE_SIGNBIT) && defined(__GNUC__) && defined(__sun) && \
     !defined(signbit)
     extern int signbit(double);
 #endif
diff --git a/ext/io/wait/wait.c b/ext/io/wait/wait.c
index eb7ed03cea..197d9b6173 100644
--- a/ext/io/wait/wait.c
+++ b/ext/io/wait/wait.c
@@ -14,7 +14,7 @@
 #include "ruby/io.h"
 
 #include <sys/types.h>
-#if defined(HAVE_UNISTD_H) && (defined(__sun) || defined(__sun__))
+#if defined(HAVE_UNISTD_H) && (defined(__sun))
 #include <unistd.h>
 #endif
 #if defined(HAVE_SYS_IOCTL_H)
diff --git a/hash.c b/hash.c
index e61f70393c..4d7cd73fc7 100644
--- a/hash.c
+++ b/hash.c
@@ -2196,7 +2196,7 @@ rb_env_path_tainted(void)
 }
 
 #if defined(_WIN32) || (defined(HAVE_SETENV) && defined(HAVE_UNSETENV))
-#elif defined __sun__
+#elif defined __sun
 static int
 in_origenv(const char *str)
 {
@@ -2284,7 +2284,7 @@ ruby_setenv(const char *name, const char *value)
 	    rb_sys_fail("unsetenv");
 #endif
     }
-#elif defined __sun__
+#elif defined __sun
     size_t len;
     char **env_ptr, *str;
     if (strchr(name, '=')) {
diff --git a/math.c b/math.c
index e9e1678dc6..2eb95dcd10 100644
--- a/math.c
+++ b/math.c
@@ -14,7 +14,7 @@
 #include <math.h>
 #include <errno.h>
 
-#if defined(HAVE_SIGNBIT) && defined(__GNUC__) && defined(__sun__) && \
+#if defined(HAVE_SIGNBIT) && defined(__GNUC__) && defined(__sun) && \
     !defined(signbit)
     extern int signbit(double);
 #endif