[MeteorsLiu]

Restore common native networking APIs and verify every retained symbol on macOS arm64 and Linux amd64/arm64.

The implementation includes:

• Generate one classified networking binding per platform from macOS 14 and Bootlin glibc 2.24 headers, using unmodified llcppg.
• Replace duplicate handwritten declarations under the established function names, remove the Native duplicates, retain the original *SockaddrIn arguments for Bind/Accept, and derive socket-storage padding constants from each native layout.
• Preserve existing *c.Char string contracts, Send/Recv length types, untyped socket constants, and macOS byte-order declarations; root c.Char and c.Printf remain unchanged.
• Remove kernel/private C entry points and the explicitly approved Linux bindresvport6 declaration, which has no libc export.
• Check every retained C function's link address and prototype ABI, all generated type layouts and constants, global symbols, and union accessors; exercise binary socket I/O, IPv4/IPv6 numeric resolution, interface enumeration, and TCP loopback.

LLGo v1.0.8 (c171abfa130108bc6451e01fcf15a8a3474eb0a7) passes executed GC and nogc tests on all three targets. These runs use the root c files from #45 at 99ddac92c7335a53a1c996174e1753bcd72c5050; merge #45 first to supply c.Iovec. Standalone CI currently stops at undefined: c.Iovec while that prerequisite is unmerged. This draft changes only c/net, with complete symbol checks making missing exports and ABI regressions visible.

[MeteorsLiu]

Merge order: #45 → #51 → #48 → #49 → #44 → #47 → #46 → #50 → #52.

This draft changes only c/net. Merge #45 first to supply the shared c.Iovec; validation used its root c files at 99ddac92c7335a53a1c996174e1753bcd72c5050 together with the current networking sources.

The current update removes duplicate Native declarations, preserves the original Bind/Accept IPv4 pointer signatures, and fixes Linux socket-storage padding constants. Existing character-pointer and Send/Recv length contracts remain compatible. Kernel/private C entry points and the explicitly approved Linux bindresvport6 declaration are excluded.

Executed llgo test -count=1 -v ./c/net runs pass on macOS arm64, Linux amd64 and Linux arm64, both with GC and -tags=nogc, using LLGo v1.0.8 (c171abfa). Every retained C function is covered by a link-address and native-prototype check; layouts, constants, globals and generated union accessors also have coverage. The PR remains draft.

Standalone CI currently stops at c/net/libc_linux_amd64.go:886:16: undefined: c.Iovec because #45 has not merged. The six passing package test runs include that documented prerequisite.