[mythtv] Current CVS breaks build on AMD64

[Angel Li]

On an AMD64 machine, this filter will not compile:

gcc -c -pipe -march=k8 -Wall -W -O3 -Wall -Wno-switch 
-fomit-frame-pointer -Wno-missing-prototypes -D_REENTRANT -DPIC -fPIC  
-DMMX -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -DPREFIX=\"/usr/local\" 
-DQT_NO_DEBUG -DQT_THREAD_SUPPORT -DQT_PLUGIN -DQT_SHARED 
-I/usr/lib64/qt-3.3/mkspecs/default -I. 
-I../../../../../../local/include 
-I../../../../../../src/linux-2.6.12-rc3/include -I../../libs/libavcodec 
-I../../libs/libmythtv -I../.. -I/usr/lib64/qt-3.3/include -o 
filter_linearblend.o filter_linearblend.c
filter_linearblend.c: In function `linearBlendFilter':
filter_linearblend.c:326: warning: empty body in an if-statement
filter_linearblend.c: In function `new_filter':
filter_linearblend.c:358: error: `linearBlendMMX' undeclared (first use 
in this function)
filter_linearblend.c:358: error: (Each undeclared identifier is reported 
only once
filter_linearblend.c:358: error: for each function it appears in.)
filter_linearblend.c:360: error: `linearBlend3DNow' undeclared (first 
use in this function)

The configure script enables "MMX":

Warning: DVB location points into kernel (ok if kernel >= 2.6.11)
# Basic Settings
Compile type     release
Compiler cache   no
DistCC           no
Install prefix   /usr/local
CPU              x86_64 (model name     : AMD Athlon(tm) 64 Processor 3000+)
Big Endian       no
MMX enabled      yes
Vector Builtins  yes

# Input Support
Joystick menu    no
lirc support     yes
ivtv support     yes
FireWire support no
DVB support      yes [/usr/src/linux-2.6.12-rc3/include]

# Sound Output Support
OSS support      yes
ALSA support     yes
aRts support     no
JACK support     no

# Video Output Support
x11 support      yes
xrandr support   yes
xv support       yes
XvMC support     yes
XvMC VLD support no
OpenGL vsync     yes
DirectFB         no