* compiler: Fix crash when using *No compiler* for building projects (reported here http://forums.codeblocks.org/index.php/topic,19071.msg131370.html#msg131370)

Changed the return type of the GetCompilerTool method, so the clients can
check if the returned value is correct or not. This requires a change to
the SDK version, because the API/ABI is broken.

git-svn-id: https://svn.code.sf.net/p/codeblocks/code/trunk@9759 2a5c6006-c6dd-42ca-98ab-0921f2732cef
- CC: fix autotools builds after rev9758

git-svn-id: https://svn.code.sf.net/p/codeblocks/code/trunk@9760 2a5c6006-c6dd-42ca-98ab-0921f2732cef