(last_mouse_glyph_frame): New var.

(last_mouse_glyph_frame): New var.
(note_mouse_movement): Say mouse moved if current frame differs
from last_mouse_glyph_frame, and update last_mouse_glyph_frame.
(XTmouse_position): Set last_mouse_glyph_frame.
(XTread_socket): Clear last_mouse_glyph_frame on mouse up/down event.
(mac_draw_string_common) [MAC_OSX && WORDS_BIG_ENDIAN]: Fix typo.
Use EndianU16_BtoN.
(mac_draw_string_common) [MAC_OSX]: Don't use ATSUClearLayoutControls.
(x_per_char_metric, XLoadQueryFont)
[MAC_OS_X_VERSION_MAX_ALLOWED < 1020]: Use device origins to get
glyph bounds.
(mac_to_x_fontname, mac_do_list_fonts)
(mac_initialize_display_info): Change screen resolutions to 72dpi.