Rework of copy mode commands ("send-keys -X") to parse the arguments so

that flags may be detected propertly rather than just looking for
strings ("-O" and so on). Also add -C and -P flags to the copy commands:
-C prevents the commands from sending the text to the clipboard and -P
prevents them from adding the text as a paste buffer.

Note some of the default key bindings change to add "--" and any similar
custom key bindings using "send-keys -X" may need a similar change.

GitHub issue 4153.

tmux.1

@@ -1801,6 +1801,7 @@ Exit copy mode.
 Clear the current selection.
 .It Xo
 .Ic copy-end-of-line
+.Op Fl CP
 .Op Ar prefix
 .Xc
 Copy from the cursor position to the end of the line.
@@ -1808,11 +1809,13 @@ Copy from the cursor position to the end of the line.
 is used to name the new paste buffer.
 .It Xo
 .Ic copy-end-of-line-and-cancel
+.Op Fl CP
 .Op Ar prefix
 .Xc
 Copy from the cursor position and exit copy mode.
 .It Xo
 .Ic copy-pipe-end-of-line
+.Op Fl CP
 .Op Ar command
 .Op Ar prefix
 .Xc
@@ -1822,6 +1825,7 @@ Copy from the cursor position to the end of the line and pipe the text to
 is used to name the new paste buffer.
 .It Xo
 .Ic copy-pipe-end-of-line-and-cancel
+.Op Fl CP
 .Op Ar command
 .Op Ar prefix
 .Xc
@@ -1830,16 +1834,19 @@ Same as
 but also exit copy mode.
 .It Xo
 .Ic copy-line
+.Op Fl CP
 .Op Ar prefix
 .Xc
 Copy the entire line.
 .It Xo
 .Ic copy-line-and-cancel
+.Op Fl CP
 .Op Ar prefix
 .Xc
 Copy the entire line and exit copy mode.
 .It Xo
 .Ic copy-pipe-line
+.Op Fl CP
 .Op Ar command
 .Op Ar prefix
 .Xc
@@ -1849,6 +1856,7 @@ Copy the entire line and pipe the text to
 is used to name the new paste buffer.
 .It Xo
 .Ic copy-pipe-line-and-cancel
+.Op Fl CP
 .Op Ar command
 .Op Ar prefix
 .Xc
@@ -1857,6 +1865,7 @@ Same as
 but also exit copy mode.
 .It Xo
 .Ic copy-pipe
+.Op Fl CP
 .Op Ar command
 .Op Ar prefix
 .Xc
@@ -1866,6 +1875,7 @@ Copy the selection, clear it and pipe its text to
 is used to name the new paste buffer.
 .It Xo
 .Ic copy-pipe-no-clear
+.Op Fl CP
 .Op Ar command
 .Op Ar prefix
 .Xc
@@ -1874,6 +1884,7 @@ Same as
 but do not clear the selection.
 .It Xo
 .Ic copy-pipe-and-cancel
+.Op Fl CP
 .Op Ar command
 .Op Ar prefix
 .Xc
@@ -1882,11 +1893,13 @@ Same as
 but also exit copy mode.
 .It Xo
 .Ic copy-selection
+.Op Fl CP
 .Op Ar prefix
 .Xc
 Copies the current selection.
 .It Xo
 .Ic copy-selection-no-clear
+.Op Fl CP
 .Op Ar prefix
 .Xc
 Same as
@@ -1894,6 +1907,7 @@ Same as
 but do not clear the selection.
 .It Xo
 .Ic copy-selection-and-cancel
+.Op Fl CP
 .Op Ar prefix
 (vi: Enter)
 (emacs: M-w)
@@ -2341,6 +2355,16 @@ variants of some commands exit copy mode after they have completed (for copy
 commands) or when the cursor reaches the bottom (for scrolling commands).
 .Ql -no-clear
 variants do not clear the selection.
+All the copy commands can take the
+.Fl C
+and
+.Fl P
+flags.
+The
+.Fl C
+flag suppresses setting the terminal clipboard when copying, while the
+.Fl P
+flag suppresses adding a paste buffer with the text.
 .Pp
 The next and previous word keys skip over whitespace and treat consecutive
 runs of either word separators or other letters as words.