To cross-compile is to build on one platform a binary that will run on another platform. When speaking of cross-compilation, it is important to distinguish between the build platform on which the compilation is performed, and the host platform on which the resulting executable is expected to run. The following configure options are used to specify each of them:
--build=build
The system on which the package is built.
--host=host
The system where built programs and libraries will run.
The --host and --build options are usually all we need for cross-compiling. The only exception is if the package being built is itself a cross-compiler: we need a third option to specify its target architecture.
--target=target
When building compiler tools: the system for which the tools will create output.
For instance when installing GCC, the GNU Compiler Collection, we can use --target=target to specify that we want to build GCC as a cross-compiler for target. Mixing --build and --target, we can actually cross-compile a cross-compiler; such a three-way cross-compilation is known as a Canadian cross.
来源：https://www.gnu.org/savannah-checkouts/gnu/automake/manual/html_node/Cross_002dCompilation.html