/bin/sh portability question

Hello,

It seems things are progressing nicely with regard to
Solaris portability.  However, I still have a few problems:

1) Maybe I didn't notice some new configuration option,
   but strcasestr is still not found with a simple "gmake".

2) In many of the shell scripts there is the idiom:

      #!/bin/sh
      
      cmd=
      path=$(dirname $0)
      case "$#" in
      0)      ;;
      *)      cmd="$1"
              shift
 
   When run, this gives the error:

      ./git.sh: syntax error at line 4: `path=$' unexpected

   I think it's because (on my Solaris at least), sh is really 
   sh and is not symlinked to bash, and sh doesn't like that 
   syntax.  Are there any good solutions to this other than
   making the administrators actually change sh to a symlink,
   (which I tried)?

/Peter