Generalise determination of LD_LIBRARY_PATH in squeak run script

[bencoman]

Following on from my mail list post...
    http://forum.world.st/Can-t-infer-base-LD-LIBRARY-PATH-td4896471.html

the `squeak` run script has LD_LIBRARY_PATH hardcoded for a dozen platforms,
but after reformatting the case statement a pattern was apparent...

    /lib/libc*)             
        SVMLLP="/lib                
           :/usr/lib";;

    /lib32/libc*)               
        SVMLLP="/lib32              
           :/usr/lib32";;

    /lib64/libc*)               
        SVMLLP="/lib64              
           :/usr/lib64";;

    /lib/tls/libc*)     
        SVMLLP="/lib/tls                        :    /lib
           :/usr/lib/tls                        :/usr/lib";;

    /lib/i386-linux-gnu/libc*)  \
        SVMLLP="/lib/i386-linux-gnu             :    /lib 
           :/usr/lib/i386-linux-gnu             :/usr/lib";;

    /lib/i386-linux-gnu/i686/cmov/libc*)    \
        SVMLLP="/lib/i386-linux-gnu/i686/cmov   :    /lib 
           :/usr/lib/i386-linux-gnu/i686/cmov   :/usr/lib";;

    /lib/386-linux-gnu/i686/cmov/libc*) \
        SVMLLP="/lib/386-linux-gnu/i686/cmov    :    /lib 
           :/usr/lib/386-linux-gnu/i686/cmov    :/usr/lib";;

    /lib/tls/i686/cmov/libc*)   \
        SVMLLP="/lib/tls/i686/cmov              :    /lib 
           :/usr/lib/tls/i686/cmov              :/usr/lib";;

    /lib/tls/i686/nosegneg/libc*)   \
        SVMLLP="/lib/i686/nosegneg/tls          :    /lib 
           :/usr/lib/i686/nosegneg/tls          :/usr/lib";;

    /lib/arm-linux-gnueabihf/libc*) \
        SVMLLP="/lib/arm-linux-gnueabihf        :    /lib 
           :/usr/lib/arm-linux-gnueabihf        :/usr/lib";;

    /lib/x86_64-linux-gnu/libc*)    \
        SVMLLP="/lib/x86_64-linux-gnu           :    /lib 
           :/usr/lib/x86_64-linux-gnu           :/usr/lib";;


that could be reduced to...
    PLATFORMLIBDIR=`expr "$LIBC_SO" : '\(.*\)/libc.*'`
    SVMLLP="$PLATFORMLIBDIR:/lib:/usr$PLATFORMLIBDIR:/usr/lib"


So this fixes my platform that the original was failing on, 
AND should work for most future platforms so users never see a failure 
for new platform that would otherwise need to another hard coded case.


Now one semantic has changed.  I couldn't determine how to run `cmd1 || cmd2` 
without it complaining about a missing cmd1 showing on the console.  
But the problem exists in original, which you can observe by swapping the
order of `/bin/uname` and `/usr/bin/uname`,  and then you get... 
     ./squeak: line 25: /usr/bin/uname: No such file or directory
So I just used plain `uname` .  Do we really care which one is used??