Introduce PYO3_NO_INTERPRETER variable for build script

build.rs

@@ -836,7 +836,25 @@ fn check_target_architecture(interpreter_config: &InterpreterConfig) -> Result<(
     Ok(())
 }
 
+fn abi3_without_interpreter() -> Result<()> {
+    println!("cargo:rustc-cfg=Py_LIMITED_API");
+    let mut flags = "FLAG_WITH_THREAD=1".to_string();
+    for minor in PY3_MIN_MINOR..=ABI3_MAX_MINOR {
+        println!("cargo:rustc-cfg=Py_3_{}", minor);
+        flags += &format!(",CFG_Py_3_{}", minor);
+    }
+    println!("cargo:rustc-cfg=py_sys_config=\"WITH_THREAD\"");
+    println!("cargo:python_flags={}", flags);
+    Ok(())
+}
+
 fn main() -> Result<()> {
+    // If PYO3_NO_INTEPRETER is set with abi3, we can build PyO3 without calling Python (UNIX only).
+    if env::var_os("PYO3_NO_INTERPRETER").is_some()
+        && env::var_os(format!("CARGO_FEATURE_ABI3_PY3{}", ABI3_MAX_MINOR)).is_some()
+    {
+        return abi3_without_interpreter();
+    }
     // 1. Setup cfg variables so we can do conditional compilation in this library based on the
     // python interpeter's compilation flags. This is necessary for e.g. matching the right unicode
     // and threading interfaces.  First check if we're cross compiling, if so, we cannot run the

guide/src/building_and_distribution.md

@@ -66,6 +66,9 @@ E.g., if you set `abi3-py36` feature, you can build `cp36-abi3-manylinux2020_x86
 To ensure ABI compatibility, we don't allow setting a minimum version higher than the system Python version.
 E.g., if you set `abi3-py38` and try to compile the crate with Python 3.6, it just fails.
 
+As an advanced feature, you can build PyO3 wheel without calling Python interpreter with
+the environment variable `PYO3_NO_INTERPRETER` set, but this only works on *NIX.
+
 ## Cross Compiling
 
 Cross compiling PyO3 modules is relatively straightforward and requires a few pieces of software: