From 35bde472b5455bab19157922dab06a5c2864bced Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Diego=20=27Flameeyes=27=20Petten=C3=B2?=
 <flameeyes@gmail.com>
Date: Tue, 20 May 2008 21:14:36 +0200
Subject: Add check for const attribute (for mathematical functions).

Add CC_ATTRIBUTE_CONST macro to the attributes.h.
Run CC_ATTRIBUTE_CONST in configure.
Define SUPPORT_ATTRIBUTE_CONST for GCC 3.
Define XINE_CONST to __attribute__((__const__)) if supported.

--HG--
extra : transplant_source : /26%26%DF%C0%3C%AC%27%5C%B7%B1y%FEQ%8Ay%EE%F1%BD
---
 configure.ac                | 1 +
 m4/attributes.m4            | 8 ++++++++
 src/xine-utils/attributes.h | 7 +++++++
 3 files changed, 16 insertions(+)

diff --git a/configure.ac b/configure.ac
index 671bd0c18..79c93f448 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2219,6 +2219,7 @@ CC_ATTRIBUTE_DEPRECATED
 CC_ATTRIBUTE_UNUSED
 CC_ATTRIBUTE_MALLOC
 CC_ATTRIBUTE_PACKED
+CC_ATTRIBUTE_CONST
 
 AC_OPTIMIZATIONS
 
diff --git a/m4/attributes.m4 b/m4/attributes.m4
index fa379a2fe..f71b3d0d0 100644
--- a/m4/attributes.m4
+++ b/m4/attributes.m4
@@ -188,6 +188,14 @@ AC_DEFUN([CC_ATTRIBUTE_PACKED], [
     [$2])
 ])
 
+AC_DEFUN([CC_ATTRIBUTE_CONST], [
+  CC_CHECK_ATTRIBUTE(
+    [const], ,
+    [int __attribute__((const)) twopow(int n) { return 1 << n; } ],
+    [$1],
+    [$2])
+])
+
 AC_DEFUN([CC_FLAG_VISIBILITY], [
   AC_REQUIRE([CC_CHECK_WERROR])
   AC_CACHE_CHECK([if $CC supports -fvisibility=hidden],
diff --git a/src/xine-utils/attributes.h b/src/xine-utils/attributes.h
index 29bb9f28f..3819818d5 100644
--- a/src/xine-utils/attributes.h
+++ b/src/xine-utils/attributes.h
@@ -45,6 +45,7 @@
 #  define SUPPORT_ATTRIBUTE_FORMAT_ARG 1
 #  define SUPPORT_ATTRIBUTE_MALLOC 1
 #  define SUPPORT_ATTRIBUTE_UNUSED 1
+#  define SUPPORT_ATTRIBUTE_CONST 1
 # endif
   
 # if __GNUC__ >= 4
@@ -109,4 +110,10 @@
 # define XINE_PACKED
 #endif
 
+#ifdef SUPPORT_ATTRIBUTE_CONST
+# define XINE_CONST __attribute__((__const__))
+#else
+# define XINE_CONST
+#endif
+
 #endif /* ATTRIBUTE_H_ */
-- 
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