build: pin -std=c11 for instrument-hooks core.c #514

Job	Run time
toolchain-detection-tests	5s
cmake-build (ubuntu-latest, off)	54s
macos-walltime-cmake-test	22s
lint	9s
cmake-build (windows-latest, off)	2m 12s
tests	12s
cmake-build (ubuntu-latest, walltime)	59s
cmake-build (windows-latest, walltime)	2m 33s
cmake-integration-tests (simulation, ubuntu-latest)	2m 16s
bazel-build (windows-latest, off, 7.6.2)	1m 31s
cmake-integration-tests (walltime, codspeed-macro)	7m 14s
bazel-build (ubuntu-latest, walltime, 9.0.0-pre.20250921.2)	58s
cmake-integration-tests (off, ubuntu-latest)	58s
bazel-integration-tests (simulation, ubuntu-latest)	1m 27s
bazel-build (ubuntu-latest, off, 9.0.0-pre.20250921.2)	1m 5s
bazel-build (ubuntu-latest, off, 7.6.2)	32s
bazel-build (ubuntu-latest, walltime, 8.4.2)	24s
bazel-build (windows-latest, walltime, 9.0.0-pre.20250921.2)	1m 2s
bazel-build (windows-latest, off, 9.0.0-pre.20250921.2)	1m 27s
bazel-build (windows-latest, walltime, 8.4.2)	2m 7s
bazel-build (windows-latest, off, 8.4.2)	1m 49s
bazel-integration-tests (walltime, codspeed-macro)	7m 32s
cmake-integration-tests (memory, ubuntu-latest)	1m 11s
bazel-build (ubuntu-latest, walltime, 7.6.2)	39s
bazel-integration-tests (memory, ubuntu-latest)	1m 51s
bazel-build (ubuntu-latest, off, 8.4.2)	33s
bazel-build (windows-latest, walltime, 7.6.2)	1m 46s
bazel-integration-tests (off, ubuntu-latest)	30s
macos-walltime-bazel-test	6m 49s
	51m 7s

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