changes.md: [6ce3c0] is fixed. Add some more "known bugs" #4660

Job	Run time
gcc	3m 21s
gcc (CFLAGS=-DTCL_NO_DEPRECATED=1)	3m 20s
gcc (--disable-shared)	3m 24s
gcc (--disable-zipfs)	3m 21s
gcc (--enable-symbols)	3m 38s
gcc (--enable-symbols=mem)	5m 14s
gcc (--enable-symbols=all)	6m 16s
gcc (CFLAGS=-ftrapv)	3m 26s
gcc (CFLAGS=-m32 CPPFLAGS=-m32 LDFLAGS=-m32 --disable-64bit)	3m 38s
	35m 38s

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