This option specifies where to find the executables, libraries,
include files, and data files of the compiler itself.
The compiler driver program runs one or more of the subprograms
cpp, cc1, as and ld. It tries prefix as a prefix for each program
it tries to run, both with and without machine/version/.
For each subprogram to be run, the compiler driver first tries the
-B prefix, if any. If that name is not found, or if -B was not
specified, the driver tries two standard prefixes, which are
/usr/lib/gcc/ and /usr/local/lib/gcc/. If neither of those results
in a file name that is found, the unmodified program name is
searched for using the directories specified in your PATH environ-
The compiler will check to see if the path provided by the -B
refers to a directory, and if necessary it will add a directory
separator character at the end of the path.
-B prefixes that effectively specify directory names also apply to
libraries in the linker, because the compiler translates these
options into -L options for the linker. They also apply to
includes files in the preprocessor, because the compiler translates
these options into -isystem options for the preprocessor. In this
case, the compiler appends include to the prefix.
The run-time support file libgcc.a can also be searched for using
the -B prefix, if needed. If it is not found there, the two stan-
dard prefixes above are tried, and that is all. The file is left
out of the link if it is not found by those means.
Another way to specify a prefix much like the -B prefix is to use
the environment variable GCC_EXEC_PREFIX.
As a special kludge, if the path provided by -B is [dir/]stageN/,
where N is a number in the range 0 to 9, then it will be replaced
by [dir/]include. This is to help with boot-strapping the com-