Deduplicate string literals and allow null bytes #239

Job	Run time
catch-bad-whitespace	4s
tests-exe (i386_linux, ubuntu-latest)	11s
tests-exe (x86_64_linux, ubuntu-latest)	10s
bootstrap-bash-2_05a	1m 20s
tests-exe (x86_64_mac, macos-latest)	14s
bootstrap-pnut-exe (bash, i386_linux)	3m 6s
bootstrap-pnut-sh (bash)	1m 12s
bootstrap-pnut-exe (bash, x86_64_linux)	3m 7s
bootstrap-pnut-sh-with-pnut-exe (i386_linux)	12s
bootstrap-pnut-sh (dash)	1m 39s
bootstrap-pnut-exe (bash, x86_64_mac)	3m 0s
bootstrap-pnut-sh-with-pnut-exe (x86_64_linux)	11s
build-without-warnings	36s
bootstrap-pnut-sh (ksh)	36s
bootstrap-pnut-exe (dash, i386_linux)	6m 24s
bootstrap-pnut-sh-with-pnut-exe (x86_64_mac)	20s
bootstrap-pnut-sh (mksh)	13m 32s
bootstrap-pnut-sh (yash)	1m 11s
bootstrap-pnut-exe (dash, x86_64_linux)	7m 12s
tests-shell (bash)	14s
bootstrap-pnut-sh (zsh)	10m 10s
tests-shell (dash)	12s
bootstrap-pnut-exe (dash, x86_64_mac)	5m 44s
tests-shell (ksh)	1s
bootstrap-pnut-exe (ksh, i386_linux)	1m 26s
tests-shell (mksh)	1s
bootstrap-pnut-exe (ksh, x86_64_linux)	1m 16s
tests-shell (yash)	1s
bootstrap-pnut-exe (ksh, x86_64_mac)	55s
tests-shell (zsh)	1s
success-message	0s
	1h 4m 18s

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