Support cross compile to different operating systems

Changelog.md

@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Fix false positive missing pyinit warning on arm64 macOS in [#673](https://github.com/PyO3/maturin/pull/673)
 * Build without rustls on arm64 Windows by nsait-linaro in [#674](https://github.com/PyO3/maturin/pull/674)
 * Publish Windows arm64 wheels to PyPI by nsait-linaro in [#675](https://github.com/PyO3/maturin/pull/675)
+* Add support for cross compiling to different operating systems in [#680](https://github.com/PyO3/maturin/pull/680)
 
 ## [0.11.5] - 2021-10-13
 

src/python_interpreter.rs

@@ -1,4 +1,5 @@
 use crate::auditwheel::PlatformTag;
+use crate::cross_compile::is_cross_compiling;
 use crate::{BridgeModel, Target};
 use anyhow::{bail, format_err, Context, Result};
 use regex::Regex;
@@ -299,7 +300,10 @@ fn fun_with_abiflags(
     target: &Target,
     bridge: &BridgeModel,
 ) -> Result<String> {
-    if bridge != &BridgeModel::Cffi && target.get_python_os() != message.platform {
+    if bridge != &BridgeModel::Cffi
+        && target.get_python_os() != message.platform
+        && !is_cross_compiling(target)?
+    {
         bail!(
             "sys.platform in python, {}, and the rust target, {:?}, don't match ಠ_ಠ",
             message.platform,