Improve documentation of gdb-mi's dedicated windows

* doc/emacs/building.texi (Other GDB Buffers): Describe the I/O
buffer and commands to show individual specialized windows.
Improve indexing.

doc/emacs/building.texi

@@ -961,9 +961,7 @@ the fringe of a source buffer to set a breakpoint there.
 @vindex gud-gdb-command-name
   To run GDB using just the GUD interaction buffer interface, without
 these additional features, use @kbd{M-x gud-gdb} (@pxref{Starting
-GUD}).  You must use this if you want to debug multiple programs
+GUD}).
-within one Emacs session, as that is currently unsupported by @kbd{M-x
-gdb}.
 
   Internally, @kbd{M-x gdb} informs GDB that its screen size is
 unlimited; for correct operation, you must not change GDB's screen
@@ -1051,9 +1049,9 @@ to restore only when @code{gdb-show-main} is non-@code{nil}.
   You may also specify additional GDB-related buffers to display,
 either in the same frame or a different one.  Select the buffers you
 want by typing @kbd{M-x gdb-display-@var{buffertype}-buffer} or
-@kbd{M-x gdb-frame-@var{buffertype}-buffer}, where @var{buffertype}
+@kbd{M-x gdb-frame-@var{buffertype}-buffer}, where @var{buffertype} is
-is the relevant buffer type, such as @samp{breakpoints}.  You can do
+the relevant buffer type, such as @samp{breakpoints} or @samp{io}.
-the same with the menu bar, with the @samp{GDB-Windows} and
+You can do the same from the menu bar, with the @samp{GDB-Windows} and
 @samp{GDB-Frames} sub-menus of the @samp{GUD} menu.
 
 @vindex gdb-max-source-window-count
@@ -1273,10 +1271,14 @@ non-@code{nil} value.
 @node Other GDB Buffers
 @subsubsection Other GDB Buffers
 
+Other buffers provided by @kbd{M-x gdb} whose display you can
+optionally request include:
+
 @table @asis
+@findex gdb-display-locals-buffer
 @item Locals Buffer
 This buffer displays the values of local variables of the current
-frame for simple data types (@pxref{Frame Info, Frame Info,
+stack frame for simple data types (@pxref{Frame Info, Frame Info,
 Information on a frame, gdb, The GNU debugger}).  Press @key{RET} or
 click @kbd{mouse-2} on the value if you want to edit it.
 
@@ -1286,20 +1288,35 @@ you can examine the value of the local variable at point by typing
 GDB, use @key{RET} or @kbd{mouse-2} on the type description
 (@samp{[struct/union]} or @samp{[array]}).  @xref{Watch Expressions}.
 
-@item Registers Buffer
+To display the Locals buffer, type @kbd{M-x gdb-display-locals-buffer}.
-@findex toggle-gdb-all-registers
-This buffer displays the values held by the registers
-(@pxref{Registers,,, gdb, The GNU debugger}).  Press @key{RET} or
-click @kbd{mouse-2} on a register if you want to edit its value.  With
-GDB 6.4 or later, recently changed register values display with
-@code{font-lock-warning-face}.
 
+@findex gdb-display-io-buffer
+@item I/O Buffer
+If the program you are debugging uses standard input and output
+streams for interaction with the user, or emits a significant amount
+of output to its standard output, you may wish to separate its I/O
+from interaction with GDB.  Use the command @w{@kbd{M-x
+gdb-display-io-buffer}} to show a window with a buffer to which Emacs
+redirects the input and output from the program you are debugging.
+
+@findex gdb-display-registers-buffer
+@item Registers Buffer
+This buffer displays the values held by the registers
+(@pxref{Registers,,, gdb, The GNU debugger}).  Request the display of
+this buffer with the command @kbd{M-x gdb-display-registers-buffer}.
+Press @key{RET} or click @kbd{mouse-2} on a register if you want to
+edit its value.  With GDB 6.4 or later, recently changed register
+values display with @code{font-lock-warning-face}.
+
+@findex gdb-display-disassembly-buffer
 @item Assembler Buffer
 The assembler buffer displays the current frame as machine code.  An
 arrow points to the current instruction, and you can set and remove
 breakpoints as in a source buffer.  Breakpoint icons also appear in
-the fringe or margin.
+the fringe or margin.  To request the display of this buffer, use
+@kbd{M-x gdb-display-disassembly-buffer}.
 
+@findex gdb-display-memory-buffer
 @item Memory Buffer
 The memory buffer lets you examine sections of program memory
 (@pxref{Memory, Memory, Examining memory, gdb, The GNU debugger}).
@@ -1307,7 +1324,8 @@ Click @kbd{mouse-1} on the appropriate part of the header line to
 change the starting address or number of data items that the buffer
 displays.  Alternatively, use @kbd{S} or @kbd{N} respectively.  Click
 @kbd{mouse-3} on the header line to select the display format or unit
-size for these data items.
+size for these data items.  Use @w{@kbd{M-x
+gdb-display-memory-buffer}} to request display of this buffer.
 @end table
 
 When @code{gdb-many-windows} is non-@code{nil}, the locals buffer