GitLab

* src/xdisp.c (font_for_underline_metrics): New function.
* src/dispextern.h: Add its prototype.
* src/xterm.c (x_draw_glyph_string):
* src/w32term.c (x_draw_glyph_string):
* src/nsterm.m (ns_draw_text_decoration): Call it.  This avoids
having identical code 3 times in 3 different files.