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Autoconf-generated
configure scripts can make decisions based on a canonical name
for the system type, or target triplet, which has the form:
‘cpu-vendor-os’, where os can be
‘system’ or ‘kernel-system’
configure can usually guess the canonical name for the type of
system it’s running on. To do so it runs a script called
config.guess, which infers the name using the uname
command or symbols predefined by the C preprocessor.
Alternately, the user can specify the system type with command line
arguments to configure (see Specifying the System Type. Doing so is
necessary when
cross-compiling. In the most complex case of cross-compiling, three
system types are involved. The options to specify them are:
the type of system on which the package is being configured and
compiled. It defaults to the result of running config.guess.
Specifying a build-type that differs from host-type enables
cross-compilation mode.
the type of system on which the package runs. By default it is the
same as the build machine. The tools that get used to build and
manipulate binaries will, by default, all be prefixed with
host-type-, such as host-type-gcc,
host-type-g++, host-type-ar, and
host-type-nm. If the binaries produced by these tools can
be executed by the build system, the configure script will make use of
it in AC_RUN_IFELSE invocations; otherwise, cross-compilation
mode is enabled. Specifying a host-type that differs
from build-type, when build-type was also explicitly
specified, equally enables cross-compilation mode.
the type of system for which any compiler tools in the package produce code (rarely needed). By default, it is the same as host.
If you mean to override the result of config.guess but
still produce binaries for the build machine, use --build,
not --host.
So, for example, to produce binaries for 64-bit MinGW, use a command like this:
./configure --host=x86_64-w64-mingw64
If your system has the ability to execute MinGW binaries but you don’t want to make use of this feature and instead prefer cross-compilation guesses, use a command like this:
./configure --build=x86_64-pc-linux-gnu --host=x86_64-w64-mingw64
Note that if you do not specify --host, configure
fails if it can’t run the code generated by the specified compiler. For
example, configuring as follows fails:
./configure CC=x86_64-w64-mingw64-gcc
When cross-compiling, configure will warn about any tools
(compilers, linkers, assemblers) whose name is not prefixed with the
host type. This is an aid to users performing cross-compilation.
Continuing the example above, if a cross-compiler named cc is
used with a native pkg-config, then libraries found by
pkg-config will likely cause subtle build failures; but using
the names x86_64-w64-mingw64-gcc and
x86_64-w64-mingw64-pkg-config
avoids any confusion. Avoiding the warning is as simple as creating the
correct symlinks naming the cross tools.
configure recognizes short aliases for many system types; for
example, ‘decstation’ can be used instead of
‘mips-dec-ultrix4.2’. configure runs a script called
config.sub to canonicalize system type aliases.
This section deliberately omits the description of the obsolete interface; see Hosts and Cross-Compilation.
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