Code:
$ gcc half-nelson.c -o half-nelson -lrt 2>&1
half-nelson.c: In function 'get_kstack':
half-nelson.c:212: error: 'MAP_32BIT' undeclared (first use in this function)
half-nelson.c:212: error: (Each undeclared identifier is reported only once
half-nelson.c:212: error: for each function it appears in.)
half-nelson.c:265: warning: integer constant is too large for 'long' type
half-nelson.c:265: warning: comparison is always true due to limited range of data type
half-nelson.c:265: warning: integer constant is too large for 'long' type
half-nelson.c:265: warning: comparison is always false due to limited range of data type
half-nelson.c:231: error: unknown register name 'r8' in 'asm'
half-nelson.c: In function 'do_child_upper':
half-nelson.c:475: warning: integer constant is too large for 'long' type