From 6f9d82c145696bedb05fe97a3d3d79900349d387 Mon Sep 17 00:00:00 2001
From: Peter Marheine <peter@taricorp.net>
Date: Sun, 3 Dec 2023 14:05:04 +1100
Subject: [PATCH] Handle OpenBSD quirks
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Closes #60, (hopefully) allowing the crate to be used on OpenBSD systems.

Suggested-by: Sébastien Bourdeauducq
---
 build.rs | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/build.rs b/build.rs
index e8a1be8..79a6958 100644
--- a/build.rs
+++ b/build.rs
@@ -298,6 +298,13 @@ fn get_system_libraries(llvm_config_path: &Path, kind: LibraryKind) -> Vec<Strin
                             return flag;
                         }
                     }
+
+                    if let Some(i) = flag.find(".so.") {
+                        // On some distributions (OpenBSD, perhaps others), we get sonames
+                        // like "-lz.so.7.0". Correct those by pruning the file extension
+                        // and library version.
+                        return &flag[..i];
+                    }
                     return flag;
                 }
 
@@ -337,6 +344,20 @@ fn get_system_libraries(llvm_config_path: &Path, kind: LibraryKind) -> Vec<Strin
         .collect()
 }
 
+/// Return additional linker search paths that should be used but that are not discovered
+/// by other means.
+///
+/// In particular, this should include only directories that are known from platform-specific
+/// knowledge that aren't otherwise discovered from either `llvm-config` or a linked library
+/// that includes an absolute path.
+fn get_system_library_dirs() -> impl IntoIterator<Item=&'static str> {
+    if target_os_is("openbsd") {
+        Some("/usr/local/lib")
+    } else {
+        None
+    }
+}
+
 fn target_dylib_extension() -> &'static str {
     if target_os_is("macos") {
         ".dylib"
@@ -358,7 +379,7 @@ fn get_system_libcpp() -> Option<&'static str> {
         // latest, at the cost of breaking the build on older OS releases
         // when LLVM was built against libstdc++.
         Some("c++")
-    } else if target_os_is("freebsd") {
+    } else if target_os_is("freebsd") || target_os_is("openbsd") {
         Some("c++")
     } else if target_env_is("musl") {
         // The one built with musl.
@@ -614,6 +635,9 @@ fn main() {
 
     // Link LLVM libraries
     println!("cargo:rustc-link-search=native={}", libdir);
+    for link_search_dir in get_system_library_dirs() {
+        println!("cargo:rustc-link-search=native={}", link_search_dir);
+    }
     // We need to take note of what kind of libraries we linked to, so that
     // we can link to the same kind of system libraries
     let (kind, libs) = get_link_libraries(&llvm_config_path, &preferences);
-- 
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