Fix build error

CC      libavdevice/alldevices.o
In file included from ./libavutil/internal.h:167:0,
                 from ./libavutil/common.h:415,
                 from ./libavutil/avutil.h:289,
                 from ./libavutil/log.h:25,
                 from libavdevice/avdevice.h:46,
                 from libavdevice/alldevices.c:22:
./libavutil/libm.h:87:40: error: static declaration of 'fminf' follows non-static declaration
 static av_always_inline av_const float fminf(float x, float y)
                                        ^
make: *** [libavdevice/alldevices.o] Error 1

using buildroot-compiled uClibc toolchain, used defconfig:

BR2_x86_64=y
BR2_x86_corei7=y
BR2_TOOLCHAIN_BUILDROOT_LARGEFILE=y
BR2_TOOLCHAIN_BUILDROOT_INET_IPV6=y
BR2_TOOLCHAIN_BUILDROOT_INET_RPC=y
BR2_TOOLCHAIN_BUILDROOT_WCHAR=y
BR2_TOOLCHAIN_BUILDROOT_CXX=y
BR2_PACKAGE_FFMPEG=y
BR2_PACKAGE_FFMPEG_GPL=y
BR2_PACKAGE_FFMPEG_NONFREE=y
BR2_PACKAGE_FFMPEG_FFPLAY=y
BR2_PACKAGE_FFMPEG_FFSERVER=y
BR2_PACKAGE_FFMPEG_AVRESAMPLE=y
BR2_PACKAGE_FFMPEG_POSTPROC=y

Patch ported from upstream commit:
http://git.videolan.org/?p=ffmpeg.git;a=commitdiff;h=4436a8f44dedc83767b3d9da9beb85d1fae2ca30

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>


From 4436a8f44dedc83767b3d9da9beb85d1fae2ca30 Mon Sep 17 00:00:00 2001
From: Carl Eugen Hoyos <cehoyos@ag.or.at>
Date: Sat, 8 Nov 2014 10:48:37 +0100
Subject: [PATCH] Remove fminf() emulation.

The emulation is unused and causes compilation trouble on systems
where fminf() is defined in <math.h> but missing from libm.
This should fix compilation on Debian powerpcspe.
---
 configure        |    2 --
 libavutil/libm.h |   10 ----------
 2 files changed, 12 deletions(-)

diff --git a/configure b/configure
index 314e7ff..978ef12 100755
--- a/configure
+++ b/configure
@@ -1678,7 +1678,6 @@ MATH_FUNCS="
     exp2
     exp2f
     expf
-    fminf
     isinf
     isnan
     ldexpf
@@ -4813,7 +4812,6 @@ disabled crystalhd || check_lib libcrystalhd/libcrystalhd_if.h DtsCrystalHDVersi
 atan2f_args=2
 ldexpf_args=2
 powf_args=2
-fminf_args=2
 
 for func in $MATH_FUNCS; do
     eval check_mathfunc $func \${${func}_args:-1}
diff --git a/libavutil/libm.h b/libavutil/libm.h
index 28d5df8..6c17b28 100644
--- a/libavutil/libm.h
+++ b/libavutil/libm.h
@@ -82,16 +82,6 @@ static av_always_inline float cbrtf(float x)
 #define exp2f(x) ((float)exp2(x))
 #endif /* HAVE_EXP2F */
 
-#if !HAVE_FMINF
-#undef fminf
-static av_always_inline av_const float fminf(float x, float y)
-{
-    //Note, the NaN special case is needed for C spec compliance, it should be
-    //optimized away if the users compiler is configured to assume no NaN
-    return x > y ? y : (x == x ? x : y);
-}
-#endif
-
 #if !HAVE_ISINF
 static av_always_inline av_const int isinf(float x)
 {
-- 
1.7.10.4