Typecast bli_getopt() return value in testsuite.
Typecast bli_getopt() return value in testsuite.

Details:
- In the test suite driver, inserted an explicit typecast of the return
  value of bli_getopt() prior parsing. The lack of typecast caused a
  problem on at least one system whereby a return value of -1 was
  interpreted as garbage character. Thanks to Francisco Igual for finding
  and submitting this fix.

scibuilder/blis,xianyi/blis,rwl/blis,audiofilter/blis,rwl/blis,rwl/blis,arm-hpc/blis,arm-hpc/blis,rwl/blis,scibuilder/blis,audiofilter/blis,xianyi/blis,scibuilder/blis,arm-hpc/blis,arm-hpc/blis,xianyi/blis,audiofilter/blis,scibuilder/blis,xianyi/blis,audiofilter/blis