GMountOperation on OpenBSD: remove the need for kvm(3)

kvm(3) is considered a deprecated interface, so make
GMountOperation::show-processes use the recommended sysctl(3) interface
instead. This also removes the need to link with libkvm.

https://bugzilla.gnome.org/show_bug.cgi?id=661835

configure.ac

@@ -165,9 +165,6 @@ case $host in
   *-*-linux*)
     os_linux=yes
     ;;
-  *-*-openbsd*)
-    os_openbsd=yes
-    ;;
 esac
 
 dnl
@@ -1314,9 +1311,6 @@ if test "x$enable_x11_backend" = xyes; then
   GTK_PACKAGES="$GTK_PACKAGES pangoft2"
 fi
 GTK_EXTRA_LIBS=
-if test x"$os_openbsd" = xyes; then
-  GTK_EXTRA_LIBS="$GTK_EXTRA_LIBS -lkvm"
-fi
 
 GTK_EXTRA_CFLAGS=
 GTK_DEP_LIBS="$GDK_EXTRA_LIBS $GTK_DEP_LIBS_FOR_X `$PKG_CONFIG --libs $PANGO_PACKAGES $GTK_PACKAGES_FOR_X $GTK_PACKAGES` $GTK_EXTRA_LIBS $MATH_LIB"