Built In GNU Functions (don't import from game)

Override in code, don't import from game:
`exit'

`malloc',
`calloc'


Can import from GNU, don't import from game:
`memchr',
`memcmp',
`memcpy',
`memset',

`strcat',
`strchr',
`strcmp',
`strcpy',
`strcspn',
`strlen',
`strncat',
`strncmp',
`strncpy',
`strpbrk',
`strrchr',
`strspn',
`strstr',

`printf',
`fprintf',
`snprintf',
`sprintf',
`vfprintf',
`vprintf',
`vsprintf'

`abs',
`fabs',
`labs',
`ceil',
`floor',
`fmod',
`modf',
`pow',
`sqrt',
`exp',

`scanf',
`sscanf',
`fputs',
`frexp',
`fscanf',

`putchar',
`puts',

`tolower',
`toupper',

`acos',
`asin',
`atan2',
`atan',
`cosh',
`cos',
`sinh',
`sin',
`tan',
`tanh',

`isalnum',
`isalpha',
`iscntrl',
`isdigit',
`isgraph',
`islower',
`isprint',
`ispunct',
`isspace',
`isupper',
`isxdigit',

`ldexp',
`log10',
`log',

Can use this to disable all:
-fno-builtin