rmagick 2.11.0 に update できない

CentOS 5.3 環境ですが、rmagick 2.9.2 から 2.11.0 にアップデートできません。

[root@test ~]# gem update rmagick
Updating installed gems
Updating rmagick
Building native extensions.  This could take a while...
ERROR:  Error installing rmagick:
        ERROR: Failed to build gem native extension.

/usr/local/bin/ruby extconf.rb
gcc -I. -I. -I/usr/local/lib/ruby/1.8/i686-linux -I. -DRUBY_EXTCONF_H=\"extconf.h\"  -fopenmp   -fPIC  -fopenmp    -c rmdraw.c
rmdraw.c: In function ‘Draw_composite’:
rmdraw.c:942: error: ‘DivideCompositeOp’ undeclared (first use in this function)
rmdraw.c:942: error: (Each undeclared identifier is reported only once
rmdraw.c:942: error: for each function it appears in.)
make: *** [rmdraw.o] エラー 1

Gem files will remain installed in /usr/local/lib/ruby/gems/1.8/gems/rmagick-2.11.0 for inspection.
Results logged to /usr/local/lib/ruby/gems/1.8/gems/rmagick-2.11.0/ext/RMagick/gem_make.out
Nothing to update

ChangeLog に思い切り書いてあった。

RMagick 2.10.0
o ImageMagick releases earlier than 6.3.5-10 and Ruby releases earlier
than 1.8.5 no longer supported.
o (Experimental) Support the use of Ruby managed memory for all memory
allocations (available in ImageMagick 6.5.3-10)
o Add Image#selective_blur_channel (available in ImageMagick 6.5.0-3)
o Add new AlphaBackgroundChannel enum value (available in ImageMagick
o Add new DistortCompositeOp enum value (available in ImageMagick 6.5.3-7)


ということは CentOS 5 系だと RMagick は 2.9.2 まで、ですかね。このためだけに ImageMagick の野良 RPM 化は必要なんだろうか...