net: config: sntp: add option for failure try interval

[maass-hamburg]

add option for a different resync interval, that is
applied when the sntp request fails.

also adds a build assert and optimisation at build time

[Copilot]

Pull Request Overview

This PR adds an option to use a distinct resynchronization interval when SNTP requests fail and includes a build assert to verify that an SNTP server is properly configured. Key changes include:

• Insertion of a BUILD_ASSERT to validate SNTP server configuration.
• Addition of an if-block in sntp_init_helper to bypass SNTP initialization when the address is empty.
• Modification of net_init_clock_via_sntp to conditionally set the resync interval based on the success or failure of the SNTP request.

Files not reviewed (1)

• subsys/net/lib/config/Kconfig: Language not supported

[Copilot]

Pull Request Overview

This PR introduces an option for a different SNTP resync interval used when SNTP requests fail, along with a build assert to ensure the SNTP server is properly configured and compile‐time optimizations.

• Adds a BUILD_ASSERT statement to validate SNTP server configuration.
• Introduces a conditional check to return an error if the SNTP server address is empty.
• Updates the reschedule work logic to use a failure-specific resync interval when needed.

Files not reviewed (1)

• subsys/net/lib/config/Kconfig: Language not supported

Comments suppressed due to low confidence (2)

subsys/net/lib/config/init_clock_sntp.c:21

• [nitpick] The use of 'sizeof(CONFIG_NET_CONFIG_SNTP_INIT_SERVER) != 1' to detect an empty address may be non-intuitive; consider adding an inline comment or refactoring the logic to improve clarity.

BUILD_ASSERT( IS_ENABLED(CONFIG_NET_CONFIG_SNTP_INIT_SERVER_USE_DHCPV4_OPTION) ||

subsys/net/lib/config/init_clock_sntp.c:24

• [nitpick] Consider enhancing the error message to specify that a valid SNTP server must be configured unless the DHCPv4 option is enabled.

"SNTP server not configured");