fixed NULL -> nullptr #345

Job	Run time
Select platforms	1s
linux-x64-hs-nopch / build (debug)	6m 7s
linux-x64-hs-minimal / build (debug)	6m 11s
linux-x64 / build (debug)	6m 11s
linux-x64 / build (release)	1m 56s
docs / build (debug)	4m 6s
linux-x64-hs-optimized / build (debug)	6m 11s
linux-x64-hs-zero / build (debug)	1m 50s
macos-aarch64 / build (debug)	1s
linux-x86 / build (debug)	46s
macos-aarch64 / build (release)	1s
macos-x64 / build (debug)	1s
linux-x86 / build (release)	1s
macos-x64 / build (release)	1s
windows-aarch64 / build (debug)	3m 46s
windows-x64 / build (debug)	1s
windows-aarch64 / build (release)	3m 20s
windows-x64 / build (release)	1s
linux-x86	1s
macos-aarch64	1s
macos-x64	1s
windows-x64	1s
linux-x64	1s
linux-cross-compile	1s
Remove bundle artifacts	2s
	40m 40s

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