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".
HOST_LONG_FORMAT ¶If defined, the string used to indicate an argument of type long
to functions like printf.  The default value is "l".
HOST_PTR_PRINTF ¶If defined, the string used to indicate an argument of type void *
to functions like printf.  The default value is "%p".
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.