INSTALL: clarify requirements and minor touch-ups #13650

Job	Run time
involved_authors_debug	7s
Sanity: Linux -Dusethreads	10m 52s
Test dist/ modules on MacOS system perl	4m 22s
ASAN (-Accflags=-DPURIFY)	21m 57s
cygwin	34m 41s
dist-modules (latest)	2m 15s
ASAN (-DDEBUGGING)	22m 24s
dist-modules (5.24)	2m 17s
ASAN (-Dusethreads)	25m 40s
install	10m 24s
dist-modules (5.10)	2m 15s
linux (-Uusethreads)	9m 46s
dist-modules (5.8)	2m 17s
linux i386/ubuntu (-Dusedevel)	15m 34s
linux (-Duseshrplib -Dusequadmath -Dusecbacktrace -Dusethreads)	12m 5s
Windows mingw64	35m 0s
linux (-Duserelocatableinc)	9m 26s
minitest	4m 6s
PERL_UNICODE (-Uusethreads)	8m 26s
linux (-Dcc='clang')	9m 46s
macOS (Monterey) 12 (-Uusethreads)	13m 16s
PERL_UNICODE (-Dusethreads -Accflags=-DPURIFY -Dcc='gcc -fsanitize=address' -Dld='gcc -fsanitize=...	23m 59s
linux (-Dcc='g++')	9m 28s
Windows msvc142	52m 27s
macOS (Monterey) 12 (-Duseithreads -Duseshrplib)	15m 36s
linux (-Accflags=-DSILENT_NO_TAINT_SUPPORT)	9m 36s
linux (-Accflags=-DNO_TAINT_SUPPORT)	9m 30s
linux (-DDEBUGGING -Accflags=-DPERL_RC_STACK)	9m 36s
linux (-Uusedl)	9m 15s
	6h 36m 23s

Provide feedback