From 3bd75cefd81c116eb4fce9115ce7593dfd0ce31f Mon Sep 17 00:00:00 2001
From: Bill Currie <bill@taniwha.org>
Date: Sun, 5 Feb 2012 14:23:33 +0900
Subject: [PATCH] Autoconfiscate log2f.

Android doesn't supply log2f for us (though it does have all the other
float calls ruamoko wants).
---
 config.d/library_functions.m4 | 8 ++++++++
 libs/ruamoko/rua_math.c       | 4 ++++
 2 files changed, 12 insertions(+)

diff --git a/config.d/library_functions.m4 b/config.d/library_functions.m4
index ea41c22aa..f36de75bf 100644
--- a/config.d/library_functions.m4
+++ b/config.d/library_functions.m4
@@ -69,3 +69,11 @@ AC_TRY_LINK(
 	AC_MSG_RESULT(no)
 )
 AM_CONDITIONAL(BUILD_GETOPT, test "x$BUILD_GETOPT" = "xyes")
+
+AC_MSG_CHECKING(for log2f)
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
+	[[#include <math.h>]], [float (*foo)(float) = log2f;])],
+	AC_DEFINE(HAVE_LOG2F, 1, [Define if you have log2f.])
+	[HAVE_LOG2F=yes],
+	[HAVE_LOG2F=no])
+AC_MSG_RESULT($HAVE_LOG2F)
diff --git a/libs/ruamoko/rua_math.c b/libs/ruamoko/rua_math.c
index c5d7ca35e..15e233c46 100644
--- a/libs/ruamoko/rua_math.c
+++ b/libs/ruamoko/rua_math.c
@@ -95,7 +95,11 @@ bi_log (progs_t *pr)
 static void
 bi_log2 (progs_t *pr)
 {
+#ifdef HAVE_LOG2F
 	R_FLOAT (pr) = log2f (P_FLOAT (pr, 0));
+#else
+	R_FLOAT (pr) = logf (P_FLOAT (pr, 0)) / M_LOG2E;
+#endif
 }
 
 static void