Some syscalls are wrongly declared "static" in solana_sdk.h, which makes clang++ assume they are local to the compilation unit. It therefore ignores the extern "C" {} block and mangles their names. While that doesn't break C++ compilation, the syscall fails at runtime with something along the lines of "ELF error: Unresolved symbol (_ZL26sol_create_program_addressPK13SolSignerSeediPK9SolPubkeyS4_)".
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