"franklynb" reported that there were 32/64 bit issues when compiling FFADO on his...

"franklynb" reported that there were 32/64 bit issues when compiling FFADO on his powerpc64 system.  After much experimenting he determined that the env.MergeFlags() call was not working.  This meant the "-m64" option was never being passed to the compiler.  His suggested fix follows the recommendation on the env.MergeFlags wiki page.

Also ensure that admin/config.guess is executed via /bin/sh explicitly.  This should result in the identification of the correct architecture even if config.guess is not set executable in the source tree.

git-svn-id: svn+ssh://ffado.org/ffado/trunk@2460 2be59082-3212-0410-8809-b0798e1608f0