libs/fst: Add fst_win_unistd.h to srcfiles.txt

Makefile

@@ -1057,6 +1057,7 @@ vcxsrc: $(GENFILES) $(EXTRA_TARGETS)
 	rm -rf yosys-win32-vcxsrc-$(YOSYS_VER){,.zip}
 	set -e; for f in `ls $(filter %.cc %.cpp,$(GENFILES)) $(addsuffix .cc,$(basename $(OBJS))) $(addsuffix .cpp,$(basename $(OBJS))) 2> /dev/null`; do \
 		echo "Analyse: $$f" >&2; cpp -std=c++17 -MM -I. -D_YOSYS_ $$f; done | sed 's,.*:,,; s,//*,/,g; s,/[^/]*/\.\./,/,g; y, \\,\n\n,;' | grep '^[^/]' | sort -u | grep -v kernel/version_ > srcfiles.txt
+	echo "libs/fst/fst_win_unistd.h" >> srcfiles.txt
 	bash misc/create_vcxsrc.sh yosys-win32-vcxsrc $(YOSYS_VER) $(GIT_REV)
 	echo "namespace Yosys { extern const char *yosys_version_str; const char *yosys_version_str=\"Yosys (Version Information Unavailable)\"; }" > kernel/version.cc
 	zip yosys-win32-vcxsrc-$(YOSYS_VER)/genfiles.zip $(GENFILES) kernel/version.cc