Remove P_ and __P macros.

Remove P_ and __P macros.

* lwlib/lwlib-Xaw.h: Remove P_ and __P macros.
* lwlib/lwlib-Xlw.h:
* lwlib/lwlib-Xm.h:
* lwlib/lwlib-int.h:
* lwlib/lwlib-utils.h:
* lwlib/lwlib.h: Likewise.

* src/buffer.h: Remove P_ and __P macros.
* src/category.h:
* src/ccl.h:
* src/character.h:
* src/charset.h:
* src/cm.h:
* src/coding.h:
* src/composite.h:
* src/dispextern.h:
* src/disptab.h:
* src/font.h:
* src/fontset.h:
* src/frame.h:
* src/gtkutil.h:
* src/indent.h:
* src/intervals.h:
* src/keyboard.h:
* src/keymap.h:
* src/lisp.h:
* src/macros.h:
* src/md5.h:
* src/menu.h:
* src/msdos.h:
* src/nsterm.h:
* src/puresize.h:
* src/region-cache.h:
* src/syntax.h:
* src/syssignal.h:
* src/systime.h:
* src/termhooks.h:
* src/w32term.h:
* src/widget.h:
* src/window.h:
* src/xgselect.h:
* src/xsettings.h:
* src/xterm.h: Likewise.