Hello raman.nain@aikar.io,
The S32 Design Studio compiler is the same as gcc and the path variable is S32DS_PA_TOOL. In order to build using this compiler, you have two options:
1. you do nothing related with the S32DS_PA_TOOL and our toolbox will add the variable in Matlab path every time you open Matlab and build the first model. It will show the following message:

2. If you want to use the compiler from another location, you go to Windows Path and put the following Variable S32DS_PA_TOOL to the location where the compiler is.

and it is S32DS_PA_TOOL not S32_DS_PA_TOOL
Hope this helps,
Marius