From e943ece38873d0cace3deebdb33ae45a40c05ec5 Mon Sep 17 00:00:00 2001
From: Marijn Suijten <marijn@traverseresearch.nl>
Date: Thu, 9 Jan 2025 14:18:21 +0100
Subject: [PATCH] Remove `build.rs` for Android when assuming API level is
 always >=21

Since Rust 1.82 the minimum Android API level is 21.  In
`backtrace`, this warranted the removal of the API version check via
`__ANDROID_API__` in https://github.com/rust-lang/backtrace-rs/pull/656
since it is now always known to be >=21.  When `findshlibs` bumps its
MSRV the same could be done.

This change is sparked by a long search for why backtraces always had
`<unknown>` symbols on Android - and when solving that by upgrading Rust
(for `std::backtrace`) or our `backtrace` dependency, why Sentry reports
did not record what images/libraries were loaded at which offsets to
resolve stack addresses back to function symbols.  It turned out that
the `xbuild` build tool never set `__ANDROID_API__` (by not telling
`clang` about the target API level via the triple) which would cause
this code to never set `feature = "dl_iterate_phdr"` to search for
libraries on Android: https://github.com/rust-mobile/xbuild/pull/209
---
 Cargo.toml        |  6 +-----
 build.rs          | 41 -----------------------------------------
 src/android-api.c |  4 ----
 src/lib.rs        | 15 ++++-----------
 4 files changed, 5 insertions(+), 61 deletions(-)
 delete mode 100644 build.rs
 delete mode 100644 src/android-api.c

diff --git a/Cargo.toml b/Cargo.toml
index 79ac814..6211774 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,15 +8,11 @@ keywords = ["dyld", "dylib", "shared", "library", "dl_iterate_phdr"]
 license = "MIT OR Apache-2.0"
 readme = "./README.md"
 repository = "https://github.com/gimli-rs/findshlibs"
+rust-version = "1.82"
 
 [dependencies]
 libc = "0.2.104"
 
-[build-dependencies]
-# Only needed for Android, but cannot be target dependent
-# https://github.com/rust-lang/cargo/issues/4932
-cc = "1.0.67"
-
 [target.'cfg(any(target_os = "macos", target_os = "ios"))'.dependencies]
 lazy_static = "1.4"
 
diff --git a/build.rs b/build.rs
deleted file mode 100644
index 29415f2..0000000
--- a/build.rs
+++ /dev/null
@@ -1,41 +0,0 @@
-extern crate cc;
-
-use std::env;
-
-fn main() {
-    match env::var("CARGO_CFG_TARGET_OS").unwrap_or_default().as_str() {
-        "android" => build_android(),
-        _ => {}
-    }
-}
-
-fn build_android() {
-    let expansion = match cc::Build::new().file("src/android-api.c").try_expand() {
-        Ok(result) => result,
-        Err(e) => {
-            println!("cargo:warning=failed to run C compiler: {}", e);
-            return;
-        }
-    };
-
-    let expansion = match std::str::from_utf8(&expansion) {
-        Ok(s) => s,
-        Err(_) => return,
-    };
-
-    let marker = "APIVERSION";
-    let i = expansion.find(marker).unwrap_or_default();
-
-    let version = expansion[i + marker.len() + 1..]
-        .split_whitespace()
-        .next()
-        .unwrap_or("");
-    let version = version.parse::<u32>().unwrap_or_else(|_| {
-        println!("cargo:warning=failed to get android api version.");
-        0
-    });
-
-    if version >= 21 {
-        println!("cargo:rustc-cfg=feature=\"dl_iterate_phdr\"");
-    }
-}
diff --git a/src/android-api.c b/src/android-api.c
deleted file mode 100644
index 8af17b4..0000000
--- a/src/android-api.c
+++ /dev/null
@@ -1,4 +0,0 @@
-// Used from the build script to detect the value of the `__ANDROID_API__`
-// builtin #define
-
-APIVERSION __ANDROID_API__
\ No newline at end of file
diff --git a/src/lib.rs b/src/lib.rs
index 08c8a94..302a967 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -100,10 +100,7 @@
 #[cfg(any(target_os = "macos", target_os = "ios"))]
 pub mod macos;
 
-#[cfg(any(
-    target_os = "linux",
-    all(target_os = "android", feature = "dl_iterate_phdr")
-))]
+#[cfg(any(target_os = "linux", target_os = "android"))]
 pub mod linux;
 
 #[cfg(target_os = "windows")]
@@ -111,14 +108,10 @@ pub mod windows;
 
 use std::ffi::OsStr;
 use std::fmt::{self, Debug};
-use std::usize;
 
 pub mod unsupported;
 
-#[cfg(any(
-    target_os = "linux",
-    all(target_os = "android", feature = "dl_iterate_phdr")
-))]
+#[cfg(any(target_os = "linux", target_os = "android"))]
 use crate::linux as native_mod;
 
 #[cfg(any(target_os = "macos", target_os = "ios"))]
@@ -131,7 +124,7 @@ use crate::windows as native_mod;
     target_os = "macos",
     target_os = "ios",
     target_os = "linux",
-    all(target_os = "android", feature = "dl_iterate_phdr"),
+    target_os = "android",
     target_os = "windows"
 )))]
 use unsupported as native_mod;
@@ -145,7 +138,7 @@ pub const TARGET_SUPPORTED: bool = cfg!(any(
     target_os = "macos",
     target_os = "ios",
     target_os = "linux",
-    all(target_os = "android", feature = "dl_iterate_phdr"),
+    target_os = "android",
     target_os = "windows"
 ));