Trivial patch attached. Fixes a Jenkins build failure: https://jenkins.freedesktop.org/job/coverity/job/coverity-scan-jhbuild/2780/console

cc  -Igdk/broadway/gdk-broadway@sta -Igdk/broadway -I../../checkout/gtk+/gdk/broadway -I. -I../../checkout/gtk+/ -Igdk -I../../checkout/gtk+/gdk -Isubprojects/libepoxy/include -I../../checkout/gtk+/subprojects/libepoxy/include -Isubprojects/libepoxy/src -I../../checkout/gtk+/subprojects/libepoxy/src -Isubprojects/libepoxy/include/epoxy -I/scratch/coverity-scan-jhbuild/install/include/gdk-pixbuf-2.0 -I/scratch/coverity-scan-jhbuild/install/include/glib-2.0 -I/scratch/coverity-scan-jhbuild/install/lib/glib-2.0/include -I/scratch/coverity-scan-jhbuild/install/include/cairo -I/scratch/coverity-scan-jhbuild/install/include/pixman-1 -I/scratch/coverity-scan-jhbuild/install/include/freetype2 -I/scratch/coverity-scan-jhbuild/install/include/harfbuzz -I/usr/include/freetype2 -I/usr/include/libpng12 -I/scratch/coverity-scan-jhbuild/install/include/pango-1.0 -I/scratch/coverity-scan-jhbuild/install/include/gio-unix-2.0/ -fdiagnostics-color=always -pipe -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -std=gnu99 -O2 -g -DG_LOG_USE_STRUCTURED=1 -DGLIB_MIN_REQUIRED_VERSION=GLIB_VERSION_2_52 -DGLIB_MAX_ALLOWED_VERSION=GLIB_VERSION_2_54 '-DGTK_VERSION="3.93.0"' -D_GNU_SOURCE -DG_ENABLE_DEBUG -DG_DISABLE_CAST_CHECKS -fPIC -pthread -DGDK_COMPILATION '-DG_LOG_DOMAIN="Gdk"' -fno-strict-aliasing -Wpointer-arith -Wmissing-declarations -Wimplicit-function-declaration -Wformat=2 -Wformat-nonliteral -Wformat-security -Wstrict-prototypes -Wmissing-prototypes -Wnested-externs -Wold-style-definition -Wundef -Wunused -Wcast-align -Wmissing-noreturn -Wmissing-format-attribute -Wmissing-include-dirs -Wlogical-op -Wswitch-default -Wswitch-enum -Wignored-qualifiers -Werror=redundant-decls -Werror=implicit -Werror=nonnull -Werror=init-self -Werror=main -Werror=missing-braces -Werror=sequence-point -Werror=return-type -Werror=trigraphs -Werror=array-bounds -Werror=write-strings -Werror=address -Werror=int-to-pointer-cast -Werror=pointer-to-int-cast -Werror=empty-body -Werror=write-strings -fvisibility=hidden -MMD -MQ 'gdk/broadway/gdk-broadway@sta/broadway-server.c.o' -MF 'gdk/broadway/gdk-broadway@sta/broadway-server.c.o.d' -o 'gdk/broadway/gdk-broadway@sta/broadway-server.c.o' -c ../../checkout/gtk+/gdk/broadway/broadway-server.c
../../checkout/gtk+/gdk/broadway/broadway-server.c:1139:24: fatal error: clienthtml.h: No such file or directory
 #include "clienthtml.h"
                        ^
compilation terminated.