(autoconf.info)Using System Type

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8.4 Using the System Type
=========================

How do you use a canonical system type?  Usually, you use it in one or
more 'case' statements in 'configure.in' to select system-specific C
files.  Then link those files, which have names based on the system
name, to generic names, such as 'host.h' or 'target.c'.  The 'case'
statement patterns can use shell wildcards to group several cases
together, like in this fragment:

     case "$target" in
     i386-*-mach* | i386-*-gnu*) obj_format=aout emulation=mach bfd_gas=yes ;;
     i960-*-bout) obj_format=bout ;;
     esac

 -- Macro: AC_LINK_FILES (SOURCE..., DEST...)
     Make 'AC_OUTPUT' link each of the existing files SOURCE to the
     corresponding link name DEST.  Makes a symbolic link if possible,
     otherwise a hard link.  The DEST and SOURCE names should be
     relative to the top level source or build directory.  This macro
     may be called multiple times.

     For example, this call:

          AC_LINK_FILES(config/${machine}.h config/${obj_format}.h, host.h object.h)

     creates in the current directory 'host.h', which is a link to
     'SRCDIR/config/${machine}.h', and 'object.h', which is a link to
     'SRCDIR/config/${obj_format}.h'.

   You can also use the host system type to find cross-compilation
tools.  Note: Generic Programs, for information about the
'AC_CHECK_TOOL' macro which does that.