[Kernel][Libc] add specifications for some GCC builtins

share/libc/__fc_gcc_builtins.h

share/libc/__fc_machdep.h

src/kernel_services/ast_queries/cil.ml

src/plugins/e-acsl/tests/arith/oracle_ci/gen_functions.c

src/plugins/e-acsl/tests/arith/oracle_ci/gen_functions_rec.c

src/plugins/e-acsl/tests/gmp-only/oracle_ci/gen_functions.c

tests/libc/more_gcc_builtins.c

tests/libc/oracle/fc_libc.0.res.oracle

tests/libc/oracle/fc_libc.1.res.oracle

tests/libc/oracle/more_gcc_builtins.res.oracle

tests/syntax/oracle/check_builtin_bts1440.res.oracle