Merge with gnulib, pacifying GCC 7

This incorporates:
2017-05-16 manywarnings: update for GCC 7
2017-05-15 sys_select: Avoid "was expanded before it was required"
* configure.ac (nw): Suppress GCC 7’s new -Wduplicated-branches and
-Wformat-overflow=2 options, due to too many false alarms.
* doc/misc/texinfo.tex, lib/strftime.c, m4/manywarnings.m4:
Copy from gnulib.
* m4/gnulib-comp.m4: Regenerate.
* src/coding.c (decode_coding_iso_2022):
Fix bug uncovered by -Wimplicit-fallthrough.
* src/conf_post.h (FALLTHROUGH): New macro.
Use it to mark all switch cases that fall through.
* src/editfns.c (styled_format): Use !, not ~, on bool.
* src/gtkutil.c (xg_check_special_colors):
When using sprintf, don’t trust Gtk to output colors in [0, 1] range.
(xg_update_scrollbar_pos): Avoid use of possibly-uninitialized bool;
this bug was actually caught by Clang.
* src/search.c (boyer_moore):
Tell GCC that CHAR_BASE, if nonzero, must be a non-ASCII character.
* src/xterm.c (x_draw_glyphless_glyph_string_foreground):
Tell GCC that glyph->u.glyphless.ch must be a character.

1 files changed, 7 insertions, 7 deletions

diff --git a/src/gtkutil.c b/src/gtkutil.c
index 1b63293fe55..16eb284d7c7 100644
--- a/src/gtkutil.c
+++ b/src/gtkutil.c
@@ -554,10 +554,11 @@ xg_check_special_colors (struct frame *f,
     else
       gtk_style_context_get_background_color (gsty, state, &col);
 
-    sprintf (buf, "rgb:%04x/%04x/%04x",
-             (unsigned) (col.red * 65535),
-             (unsigned) (col.green * 65535),
-             (unsigned) (col.blue * 65535));
+    unsigned short
+      r = col.red * 65535,
+      g = col.green * 65535,
+      b = col.blue * 65535;
+    sprintf (buf, "rgb:%04x/%04x/%04x", r, g, b);
     success_p = x_parse_color (f, buf, color) != 0;
 #else
     GtkStyle *gsty = gtk_widget_get_style (FRAME_GTK_WIDGET (f));
@@ -3856,7 +3857,6 @@ xg_update_scrollbar_pos (struct frame *f,
       GtkWidget *wparent = gtk_widget_get_parent (wscroll);
       gint msl;
       int scale = xg_get_gdk_scale ();
-      bool hidden;
 
       top /= scale;
       left /= scale;
@@ -3875,13 +3875,13 @@ xg_update_scrollbar_pos (struct frame *f,
       /* Move and resize to new values.  */
       gtk_fixed_move (GTK_FIXED (wfixed), wparent, left, top);
       gtk_widget_style_get (wscroll, "min-slider-length", &msl, NULL);
-      if (msl > height)
+      bool hidden = height < msl;
+      if (hidden)
         {
           /* No room.  Hide scroll bar as some themes output a warning if
              the height is less than the min size.  */
           gtk_widget_hide (wparent);
           gtk_widget_hide (wscroll);
-	  hidden = true;
         }
       else
         {