configure error on blas shell variable test

[Mike Miller]

Rik,

I get a shell syntax error when running configure on a system without a
BLAS library, instead of a proper error message exit. The error is due
to lines like

  if test $ax_blas_f77_func_ok = no; then

where the variable may not actually have a value. The error looks like

  ../configure: line 32752: test: =: unary operator expected
  ../configure: line 34261: test: =: unary operator expected
  ../configure: line 35815: test: =: unary operator expected

Your changeset ad2c3902b826 got rid of the quotes in that test, which is
fine for most cases but apparently can still fail if the BLAS library
isn't even present.

Which style do you prefer for consistency, restoring the quotes or
setting that variable to "no" before calling AX_BLAS_WITH_F77_FUNC? The
macro doesn't seem to care whether it already has a value.

-- 
mike