[legal] Add a selection of FILE_LICENCE declarations

Add FILE_LICENCE declarations to almost all files that make up the
various standard builds of gPXE.

src/hci/mucurses/ansi_screen.c

@@ -2,6 +2,8 @@
 #include <curses.h>
 #include <console.h>
 
+FILE_LICENCE ( GPL2_OR_LATER );
+
 static void ansiscr_reset(struct _curses_screen *scr) __nonnull;
 static void ansiscr_movetoyx(struct _curses_screen *scr,
                                unsigned int y, unsigned int x) __nonnull;

src/hci/mucurses/clear.c

@@ -8,6 +8,8 @@
  *
  */
 
+FILE_LICENCE ( GPL2_OR_LATER );
+
 /**
  * Clear a window to the bottom from current cursor position
  *

src/hci/mucurses/colour.c

@@ -1,5 +1,7 @@
 #include <curses.h>
 
+FILE_LICENCE ( GPL2_OR_LATER );
+
 struct colour_pair {
 	short fcol;
 	short bcol;

src/hci/mucurses/cursor.h

@@ -7,6 +7,8 @@
  *
  */
 
+FILE_LICENCE ( GPL2_OR_LATER );
+
 struct cursor_pos {
 	unsigned int y, x;
 };

src/hci/mucurses/mucurses.c

@@ -8,6 +8,8 @@
  *
  */
 
+FILE_LICENCE ( GPL2_OR_LATER );
+
 static void _wupdcurs ( WINDOW *win ) __nonnull;
 void _wputch ( WINDOW *win, chtype ch, int wrap ) __nonnull;
 void _wputc ( WINDOW *win, char c, int wrap ) __nonnull;

src/hci/mucurses/mucurses.h

@@ -7,6 +7,8 @@
  *
  */
 
+FILE_LICENCE ( GPL2_OR_LATER );
+
 #define WRAP 0
 #define NOWRAP 1
 

src/hci/mucurses/print.c

@@ -10,6 +10,8 @@
  *
  */
 
+FILE_LICENCE ( GPL2_OR_LATER );
+
 /**
  * Add a single-byte character and rendition to a window and advance
  * the cursor

src/hci/mucurses/widgets/editbox.c

@@ -16,6 +16,8 @@
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
+FILE_LICENCE ( GPL2_OR_LATER );
+
 #include <string.h>
 #include <assert.h>
 #include <gpxe/editbox.h>

src/hci/mucurses/winattrs.c

@@ -6,6 +6,8 @@
  *
  */
 
+FILE_LICENCE ( GPL2_OR_LATER );
+
 /**
  * Get the background rendition attributes for a window
  *

src/hci/mucurses/wininit.c

@@ -7,6 +7,8 @@
  *
  */
 
+FILE_LICENCE ( GPL2_OR_LATER );
+
 /**
  * Initialise console environment
  *