lal_matmix: trying a different way to get a GST_COMPLEX_FLOAT without angering the CI

gst/lal/gstlal_matmix.c

@@ -252,7 +252,9 @@ static GstFlowReturn mix(GSTLALMatMix *element, GstBuffer *inbuf, GstBuffer *out
 			GST_ELEMENT_ERROR(element, STREAM, FAILED, (NULL), ("%p: buffer size does not match channel and sample count", inbuf));
 			return GST_FLOW_NOT_NEGOTIATED;
 		}
-		gsl_blas_cgemm(CblasNoTrans, CblasNoTrans, (gsl_complex_float) GSL_COMPLEX_ONE, &input_channels.matrix, &element->mixmatrix_cs.matrix, (gsl_complex_float) GSL_COMPLEX_ZERO, &output_channels.matrix);
+		complex float float_one = 1.0 + 0.0 * I;
+		complex float float_zero = 0.0 + 0.0 * I;
+		gsl_blas_cgemm(CblasNoTrans, CblasNoTrans, (gsl_complex_float) float_one, &input_channels.matrix, &element->mixmatrix_cs.matrix, (gsl_complex_float) float_zero, &output_channels.matrix);
 		break;
 	}