maint: Remove return stmts after gripe function calls. * gripes.h: Mark gripe functions which call error() wwith GCC_ATTR_NORETURN. * jit-typeinfo.cc (gripe_bad_result): Mark function with GCC_ATTR_NORETURN. * load-save.cc (gripe_file_open): Mark function with GCC_ATTR_NORETURN. * ov-base.cc (gripe_indexed_assignment, gripe_assign_conversion_failed, gripe_no_conversion): Mark functions with GCC_ATTR_NORETURN. * ov-class.cc (gripe_invalid_index1, gripe_invalid_index_for_assignment, gripe_invalid_index_type): Mark functions with GCC_ATTR_NORETURN. * ov-classdef.h (gripe_invalid_object): Mark function with GCC_ATTR_NORETURN. * ov.cc (gripe_cat_op, gripe_cat_op_conv): Mark functions with GCC_ATTR_NORETURN. * balance.cc, det.cc, eig.cc, hess.cc, inv.cc, jit-typeinfo.cc, load-save.cc, qz.cc, schur.cc, sparse-xdiv.cc, sparse-xpow.cc, sylvester.cc, xdiv.cc, xpow.cc, symrcm.cc, ov-base.cc, ov-classdef.h, ov-cs-list.cc, ov-flt-re-mat.cc, ov-re-mat.cc, ov-re-sparse.cc, ov.cc, op-int.h, op-fs-fs.cc, ops.h: Remove statements that occur after a gripe function which does not return. * op-cs-cs.cc, op-dms-template.cc, op-fcs-fcs.cc, op-s-s.cc : Add newline between gripe and return statement for readability.

--- a/libinterp/operators/op-fcs-fcs.cc	Thu Dec 31 17:06:36 2015 -0500
+++ b/libinterp/operators/op-fcs-fcs.cc	Fri Jan 01 13:58:45 2016 -0800
@@ -44,6 +44,7 @@
   FloatComplex x = v.float_complex_value ();
   if (xisnan (x))
     gripe_nan_to_logical_conversion ();
+
   return octave_value (x == 0.0f);
 }