ifstat: fix build with GCC 15 #27712

Job	Run time
Test Formalities	16s
Feeds Package Test Build / Test aarch64_generic	44m 15s
Feeds Package Test Build / Test i386_pentium-mmx	46m 2s
Feeds Package Test Build / Test arm_cortex-a15_neon-vfpv4	56m 5s
Feeds Package Test Build / Test x86_64	52m 54s
Feeds Package Test Build / Test mips_24kc	45m 3s
Feeds Package Test Build / Test powerpc_464fp	40m 38s
Feeds Package Test Build / Test powerpc_8548	41m 45s
Feeds Package Test Build / Test mipsel_24kc	37m 50s
Feeds Package Test Build / Test riscv64_generic	47m 40s
Feeds Package Test Build / Test arm_cortex-a9_vfpv3-d16	49m 57s
	7h 42m 25s

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