Fix function prototype declarations for cross-platform compatibility

[devin-ai-integration]

Summary

Fixes a compilation error that occurs on some Linux distros with stricter compilers:

error: too many arguments to function 'close_unix_socket'; expected 0, have 1
error: conflicting types for 'close_unix_socket'; have 'void(int)'

The root cause was close_unix_socket() being declared with no parameters in the header but defined with int server_fd in the implementation. This PR fixes that mismatch and proactively updates other function declarations from () to (void) for C standards compliance.

Changes:

• Fix close_unix_socket signature mismatch in unix_socket.h
• Update empty () declarations to (void) in headers and definitions for: setup_unix_socket, watchdog_init, scan_cycle_time_start, scan_cycle_time_end
• Update function pointer typedefs in plugin_driver.h to use (void)
• Make store_on_buffer and retrieve_from_buffer static in log.c (internal functions)

Verified build passes with strict compiler flags: -Wall -Wextra -Werror -Wstrict-prototypes -Wold-style-definition

Review & Testing Checklist for Human

• Verify close_unix_socket(int server_fd) signature in header matches the implementation (line 10 of unix_socket.h)
• Test compilation on the distro that was originally failing (the one that reported the error)
• If native plugins are in use, verify they still work after the function pointer typedef changes in plugin_driver.h

Recommended test plan: Build and run the PLC runtime on the distro that was originally failing to confirm the compilation error is resolved.

Notes

Link to Devin run: https://app.devin.ai/sessions/6bc2817257fc4494aaa3e09ad67875f2
Requested by: Thiago Alves (@thiagoralves)

[devin-ai-integration]

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[Copilot]

Pull request overview

This PR addresses compilation errors on strict C compilers by fixing function prototype mismatches and standardizing empty parameter lists to use (void) instead of () for C standards compliance.

Key changes:

• Fixed close_unix_socket signature mismatch between header declaration and implementation
• Updated all empty parameter list declarations from () to (void) across headers and implementations
• Made internal logging buffer functions static to improve encapsulation

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
core/src/plc_app/utils/watchdog.h	Updated watchdog_init declaration to use (void)
core/src/plc_app/utils/watchdog.c	Updated watchdog_init definition to use (void) and reordered includes alphabetically
core/src/plc_app/utils/log.c	Made store_on_buffer and retrieve_from_buffer static, updated retrieve_from_buffer to use (void), and reformatted long lines
core/src/plc_app/unix_socket.h	Fixed close_unix_socket signature to accept int server_fd parameter and updated setup_unix_socket to use (void)
core/src/plc_app/unix_socket.c	Updated setup_unix_socket definition to use (void)
core/src/plc_app/scan_cycle_manager.h	Updated scan_cycle_time_start and scan_cycle_time_end declarations to use (void)
core/src/plc_app/scan_cycle_manager.c	Updated scan_cycle_time_start and scan_cycle_time_end definitions to use (void)
core/src/drivers/plugin_driver.h	Updated function pointer typedefs to use (void) for empty parameter lists

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