When you configure GNU CC using the `configure' script (see section Installing GNU CC), it will construct the file `Makefile' from the template file `Makefile.in'. When it does this, it will incorporate makefile fragment files from the `config' directory, named `t-target' and `x-host'. If these files do not exist, it means nothing needs to be added for a given target or host.
The target makefile fragment, `t-target', defines special target dependent variables and targets used in the `Makefile':
LIBGCC1
CROSS_LIBGCC1
LIBGCC2_CFLAGS
LIB2FUNCS_EXTRA
CRTSTUFF_T_CFLAGS
MULTILIB_OPTIONS
MULTILIB_OPTIONS
macro lists the set of options for which
special versions of `libgcc.a' must be built. Write options that
are mutually incompatible side by side, separated by a slash. Write
options that may be used together separated by a space. The build
procedure will build all combinations of compatible options.
For example, if you set MULTILIB_OPTIONS
to `m68000/m68020
msoft-float', `Makefile' will build special versions of
`libgcc.a' using the options `-m68000', `-m68020',
`-msoft-float', `-m68000 -msoft-float', and `-m68020
-msoft-float'.
MULTILIB_DIRNAMES
MULTILIB_OPTIONS
is used, this variable specifies the
directory names that should be used to hold the various libraries.
Write one element in MULTILIB_DIRNAMES
for each element in
MULTILIB_OPTIONS
. If MULTILIB_DIRNAMES
is not used, the
default value will be MULTILIB_OPTIONS
, with all slashes treated
as spaces.
For example, if MULTILIB_OPTIONS
is `m68000/m68020
msoft-float', then the default value of MULTILIB_DIRNAMES
is
`m68000 m68020 msoft-float'. You may specify a different value if
you desire a different set of directory names.
MULTILIB_MATCHES
MULTILIB_OPTIONS
, GNU CC needs to know about
any synonyms. In that case, set MULTILIB_MATCHES
to a list of
items of the form `option=option' to describe all relevant
synonyms. For example, `m68000=mc68000 m68020=mc68020'.
The host makefile fragment, `x-host', defines special host dependent variables and targets used in the `Makefile':
CC
CLIB
OLDCC
OLDAR
ar
to use when building `libgcc1.a' for a native
compilation.
INSTALL