emacs-26 build breaking on RHEL 6.6 GTK2

[Kaushal Modi]

Hello,

emacs-26 build is breaking after the last 2 commits ([1], [2]) related to GTK. This is after "make bootstrap".

First I get this warning:

xfns.c: In function ‘Fx_display_monitor_attributes_list’:
xfns.c:4993:15: warning: implicit declaration of function ‘gdk_screen_get_monitor_scale_factor’ [-Wimplicit-function-declaration]
       scale = gdk_screen_get_monitor_scale_factor (gscreen, i);
               ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
xfns.c:4993:7: warning: nested extern declaration of ‘gdk_screen_get_monitor_scale_factor’ [-Wnested-externs]
       scale = gdk_screen_get_monitor_scale_factor (gscreen, i);
       ^~~~~
  CC       xselect.o

And then this error:

  CC       lastfile.o
make -C ../admin/charsets all
make[2]: Entering directory '/home/kmodi/downloads/git/emacs/admin/charsets'
make[2]: Nothing to be done for 'all'.
make[2]: Leaving directory '/home/kmodi/downloads/git/emacs/admin/charsets'
make -C ../admin/unidata charscript.el
make[2]: Entering directory '/home/kmodi/downloads/git/emacs/admin/unidata'
make[2]: Nothing to be done for 'charscript.el'.
make[2]: Leaving directory '/home/kmodi/downloads/git/emacs/admin/unidata'
  CCLD     temacs
xfns.o: In function `Fx_display_monitor_attributes_list':
xfns.c:(.text+0x9ab3): undefined reference to `gdk_screen_get_monitor_scale_factor'
collect2: error: ld returned 1 exit status
make[1]: *** [Makefile:600: temacs] Error 1

Here is my Emacs build info from the last successful build (yesterday):

Emacs version: GNU Emacs 26.0.91 (build 1, x86_64-pc-linux-gnu, GTK+ Version 2.24.23)
 of 2018-01-23, built using commit 1fc98ed073a2d26ad941748ecb13aa6f47dd7b01.

./configure options:
  --with-modules --prefix=/home/kmodi/usr_local/apps/6/emacs/emacs-26 '--program-transform-name=s/^ctags$/ctags_emacs/' --enable-checking=yes,glyphs --enable-check-lisp-object-type 'CPPFLAGS=-I/home/kmodi/usr_local/6/include -I/usr/include/freetype2 -I/usr/include' 'CFLAGS=-ggdb3 -O0' 'CXXFLAGS=-ggdb3 -O0' 'LDFLAGS=-L/home/kmodi/usr_local/6/lib -L/home/kmodi/usr_local/6/lib64 -ggdb3' PKG_CONFIG_PATH=/home/kmodi/usr_local/6/lib/pkgconfig:/home/kmodi/usr_local/6/lib64/pkgconfig:/cad/adi/apps/gnu/linux/x86_64/6/lib/pkgconfig:/cad/adi/apps/gnu/linux/x86_64/6/lib64/pkgconfig:/home/kmodi/stowed/lib/pkgconfig:/usr/lib/pkgconfig:/usr/lib64/pkgconfig:/usr/share/pkgconfig:/lib/pkgconfig:/lib64/pkgconfig

Features:
  XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GSETTINGS NOTIFY ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE LIBOTF XFT ZLIB TOOLKIT_SCROLL_BARS GTK2 X11 MODULES THREADS

Thanks.

[1]: http://git.savannah.gnu.org/cgit/emacs.git/commit/?h=emacs-26&id=2892f05792e1f52b0966f92c5ed1aa75dcdd66a3
[2]: http://git.savannah.gnu.org/cgit/emacs.git/commit/?h=emacs-26&id=59db8dca030ba6a34d143c3cc6715f02beba1068

--

Kaushal Modi