maint: Use parentheses around condition for switch(),while(),if() statements. * libinterp/corefcn/dirfns.cc, libinterp/octave-value/ov-fcn-handle.cc, liboctave/array/Sparse.cc, scripts/image/rgb2ind.m, scripts/io/importdata.m, scripts/io/strread.m, scripts/optimization/fminbnd.m, scripts/optimization/sqp.m, scripts/plot/graphics_toolkit.m, scripts/plot/hdl2struct.m, scripts/plot/legend.m, scripts/plot/print.m, scripts/plot/printd.m, scripts/plot/private/__contour__.m, scripts/plot/private/__go_draw_axes__.m, scripts/plot/struct2hdl.m, scripts/polynomial/polyeig.m, scripts/sparse/bicg.m, scripts/specfun/ellipke.m, scripts/special-matrix/gallery.m, scripts/ui/errordlg.m, scripts/ui/helpdlg.m, scripts/ui/inputdlg.m, scripts/ui/listdlg.m, scripts/ui/questdlg.m, scripts/ui/warndlg.m: Use parentheses around condition for switch(),while(),if() statements.

--- a/scripts/polynomial/polyeig.m
+++ b/scripts/polynomial/polyeig.m
@@ -46,13 +46,13 @@
   n = zeros (1, nin);
 
   for cnt = 1 : nin
-    if ! ( issquare (varargin{cnt}) )
+    if (! issquare (varargin{cnt}))
        error ("polyeig: coefficients must be square matrices");
     endif
     n(cnt) = size (varargin{cnt}, 1);
   endfor
 
-  if numel (unique (n)) > 1
+  if (numel (unique (n)) > 1)
        error ("polyeig: coefficients must have the same dimensions");
   endif
   n = unique (n);