maint: silence several compiler warnings when building for Windows * sighandlers.cc (w32_interrupt_manager::do_jump_to_enclosing_context): Use reinterpret_cast to silence compiler warning from -Wold-style-cast. * welcome-wizard.cc (welcome_wizard::welcome_wizard): Likewise. * oct-procbuf.cc (octave_procbuf_list): Only define on systems that use it to silence compiler warning from -Wunused-variable. * sysdep.cc (w32_shell_execute): Delete empty unused function to silence several compiler warnings. (raw_mode): Use octave_unused_parameter to silence compiler warnings from -Wunused-parameter on certain systems. * cdisplay.c (octave_get_display_info): Use octave_unused_parameter to silence compiler warning from -Wunused-parameter on certain systems. * oct-group.cc (octave::sys::group::getgrgid, octave::sys::group::getgrnam, octave::sys::group::group): Likewise. * oct-passwd.cc (octave::sys::password::getpwuid, octave::sys::password::getpwnam, octave::sys::password::password): Likewise. * signal-wrappers.c (octave_kill_wrapper, block_or_unblock_signal): Likewise. * wait-for-input.c (octave_wait_for_input): Likewise. * unistd-wrappers.c (prepare_spawn): Add const-qualifier on argument to silence compiler warning from -Wdiscarded-qualifiers. * stat-wrappers.c: Use pragma to disable -Wunused-parameter warnings for wrapper functions around macros that may discard their arguments on certain systems. * wait-wrappers.c Use pragma to disable -Wunused-parameter warnings for wrapper functions around macros that may discard their arguments on certain systems. Reorder functions to group related wrappers. (octave_waitpid_wrapper): Use octave_unused_parameter to silence compiler warning from -Wunused-parameter on certain systems.

--- a/libinterp/corefcn/cdisplay.c	Thu Sep 28 21:08:51 2017 -0700
+++ b/libinterp/corefcn/cdisplay.c	Sun Oct 01 14:52:33 2017 -0700
@@ -57,6 +57,8 @@
 
 #if defined (OCTAVE_USE_WINDOWS_API)
 
+  octave_unused_parameter (dpy_name);
+
   HDC hdc = GetDC (0);
 
   if (hdc)
@@ -79,6 +81,8 @@
 
 #elif defined (HAVE_FRAMEWORK_CARBON)
 
+  octave_unused_parameter (dpy_name);
+
   CGDirectDisplayID display = CGMainDisplayID ();
 
   if (display)
@@ -163,6 +167,7 @@
 
 #else
 
+  octave_unused_parameter (dpy_name);
   octave_unused_parameter (ht);
   octave_unused_parameter (wd);
   octave_unused_parameter (dp);