gnu17 is now the platform default. am: d41e3b282d am: c0ecb97421 am: 43b5a8206d am: 7860cc2cea

Original change: https://android-review.googlesource.com/c/platform/external/libwebsockets/+/2626762

Change-Id: I9f6e7cd9c8b68f289ab2c161e6ad29839e0b06a4
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>