outdxf: fix old LTYPE #4706

Job	Run time
linux-cmake	5m 12s
linux (CFLAGS="-O1 -fno-omit-frame-pointer -fsanitize=address -fno-var-tracking" --disable-bindin...	15m 35s
macOS	10m 21s
linux (CC="clang")	10m 54s
mingw	26m 46s
linux (--enable-release)	26m 56s
linux (--enable-gcov --disable-bindings --disable-docs CFLAGS="-O0 -g")	7m 46s
mingw-cmake	6m 57s
linux (--disable-write --disable-docs)	9m 54s
mips32-big-endian	26m 55s
linux (CFLAGS="-O2 -m32" --disable-bindings --disable-docs)	12m 44s
ppc64-big-endian	13m 35s
linux (CFLAGS="-O2 -fno-omit-frame-pointer -fsanitize=undefined -fno-var-tracking" --disable-bind...	26m 54s
vs2019	4m 50s
vs2019-ninja	4m 23s
	3h 29m 42s

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