Host Misc - GNU Compiler Collection (GCC) Internals

16.3 Host Misc

FATAL_EXIT_CODE: A C expression for the status code to be returned when the compiler exits after serious errors. The default is the system-provided macro `EXIT_FAILURE', or `1' if the system doesn't define that macro. Define this macro only if these defaults are incorrect.
SUCCESS_EXIT_CODE: A C expression for the status code to be returned when the compiler exits without serious errors. (Warnings are not serious errors.) The default is the system-provided macro `EXIT_SUCCESS', or `0' if the system doesn't define that macro. Define this macro only if these defaults are incorrect.
USE_C_ALLOCA: Define this macro if GCC should use the C implementation of alloca provided by libiberty.a. This only affects how some parts of the compiler itself allocate memory. It does not change code generation.
When GCC is built with a compiler other than itself, the C alloca is always used. This is because most other implementations have serious bugs. You should define this macro only on a system where no stack-based alloca can possibly work. For instance, if a system has a small limit on the size of the stack, GCC's builtin alloca will not work reliably.
COLLECT2_HOST_INITIALIZATION: If defined, a C statement (sans semicolon) that performs host-dependent initialization when collect2 is being initialized.
GCC_DRIVER_HOST_INITIALIZATION: If defined, a C statement (sans semicolon) that performs host-dependent initialization when a compilation driver is being initialized.
HOST_LONG_LONG_FORMAT: If defined, the string used to indicate an argument of type long long to functions like printf. The default value is "ll".

In addition, if configure generates an incorrect definition of any of the macros in auto-host.h, you can override that definition in a host configuration header. If you need to do this, first see if it is possible to fix configure.