Add lib/builtin.c to win32/build-tcc.bat

It looks like this is in the Makefile build, and it appears to be
necessary to make __builtin_ctzll available.

win32/build-tcc.bat

@@ -200,7 +200,8 @@ exit /B %ERRORLEVEL%
 .\tcc -B. -m%1 -c ../lib/alloca.S
 .\tcc -B. -m%1 -c ../lib/alloca-bt.S
 .\tcc -B. -m%1 -c ../lib/stdatomic.c
-.\tcc -B. -m%1 -ar lib/%2libtcc1.a libtcc1.o crt1.o crt1w.o wincrt1.o wincrt1w.o dllcrt1.o dllmain.o chkstk.o alloca.o alloca-bt.o stdatomic.o
+.\tcc -B. -m%1 -c ../lib/builtin.c
+.\tcc -B. -m%1 -ar lib/%2libtcc1.a libtcc1.o crt1.o crt1w.o wincrt1.o wincrt1w.o dllcrt1.o dllmain.o chkstk.o alloca.o alloca-bt.o stdatomic.o builtin.o
 .\tcc -B. -m%1 -c ../lib/bcheck.c -o lib/%2bcheck.o -bt -I..
 .\tcc -B. -m%1 -c ../lib/bt-exe.c -o lib/%2bt-exe.o
 .\tcc -B. -m%1 -c ../lib/bt-log.c -o lib/%2bt-log.o