ICU-22916 Remove use of makedep from MVS build, update doc #2885

Job	Run time
clang-valgrind-test	9m 55s
clang-valgrind-intltest (utility)	7m 0s
clang-valgrind-intltest (normalize)	6m 52s
clang-valgrind-intltest (collator)	5m 13s
clang-valgrind-intltest (regex)	5m 13s
clang-valgrind-intltest (format)	16m 7s
clang-valgrind-intltest (translit)	5m 54s
clang-valgrind-intltest (rbbi)	7m 32s
clang-valgrind-intltest (rbnf)	6m 34s
clang-valgrind-intltest (rbnfrt)	5m 58s
clang-valgrind-intltest (icuserv)	5m 22s
clang-valgrind-intltest (idna)	5m 27s
clang-valgrind-intltest (convert)	6m 55s
clang-valgrind-intltest (rbnfp)	5m 7s
clang-valgrind-intltest (csdet)	5m 8s
clang-valgrind-intltest (spoof)	5m 9s
clang-valgrind-intltest (bidi)	5m 29s
	1h 54m 55s

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