(cherry-pick): Fix warning when building on Linux #1503

Job	Run time
build (gcc)	1m 58s
build (gcc, CFLAGS=-DTK_NO_DEPRECATED=1)	2m 0s
build (gcc, --disable-xft)	1m 40s
build (gcc, --disable-xss)	1m 39s
build (gcc, --enable-symbols)	1m 42s
test (gcc)	4m 26s
build (clang)	1m 52s
test (gcc, --disable-xft)	4m 4s
build (clang, CFLAGS=-DTK_NO_DEPRECATED=1)	2m 9s
test (gcc, --enable-symbols)	3m 37s
build (clang, --disable-xft)	2m 27s
build (clang, --disable-xss)	1m 50s
build (clang, --enable-symbols)	2m 2s
	31m 26s

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