diagnose, rpc: fix compilation with boost 1.87 #3188

Job	Run time
Lint	54s
ARM [GOAL install] [buster]	7m 46s
Win32	8m 8s
macOS 13 native [GOAL install] [GUI] [no depends]	22m 15s
Win64	7m 45s
i386 Linux [GOAL install] [focal]	7m 45s
x86_64 Linux [GOAL install] [GUI] [focal] [no depends]	2m 22s
x86_64 Linux [GOAL install] [GUI] [bionic] [no depends]	7m 27s
x86_64 Linux [ASan] [LSan] [UBSan] [integer] [jammy] [no depends]	7m 44s
macOS 10.14 [GOAL deploy] [GUI] [no tests] [noble]	7m 44s
arm64 macOS 10.14 [GOAL deploy] [GUI] [no tests] [noble]	7m 44s
	1h 27m 34s

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