From 95a42ae38fed8ef0b0dd07b2568b649c1d7a9aeb Mon Sep 17 00:00:00 2001
From: Hilton Chain <hako@ultrarare.space>
Date: Wed, 27 Nov 2024 11:54:51 +0800
Subject: [PATCH] Use system paths.

Prefer Guix search paths and support Guix cross builds.
---
 lib/std/zig/system/NativePaths.zig      | 56 ++++++++++++++++++++++++-
 lib/std/zig/system/NativeTargetInfo.zig | 25 +++++++++--
 src/main.zig                            |  3 +-
 3 files changed, 78 insertions(+), 6 deletions(-)

diff --git a/lib/std/zig/system/NativePaths.zig b/lib/std/zig/system/NativePaths.zig
index 2c4db3ec85..6366e37cd9 100644
--- a/lib/std/zig/system/NativePaths.zig
+++ b/lib/std/zig/system/NativePaths.zig
@@ -25,7 +25,53 @@ pub fn detect(allocator: Allocator, native_info: NativeTargetInfo) !NativePaths
         .warnings = ArrayList([:0]u8).init(allocator),
     };
     errdefer self.deinit();
-
+    if (isGuix(allocator)) {
+        const guix_cross_include_paths = [_][]const u8{ "CROSS_C_INCLUDE_PATH", "CROSS_CPLUS_INCLUDE_PATH" };
+        for (guix_cross_include_paths) |env_var| {
+            if (process.getEnvVarOwned(allocator, env_var)) |include_path| {
+                var it = mem.tokenize(u8, include_path, ":");
+                while (it.next()) |dir|
+                    try self.addIncludeDir(dir);
+            } else |err| switch (err) {
+                error.InvalidUtf8 => {},
+                error.EnvironmentVariableNotFound => {},
+                error.OutOfMemory => |e| return e,
+            }
+        }
+        if (process.getEnvVarOwned(allocator, "CROSS_LIBRARY_PATH")) |library_path| {
+            var it = mem.tokenize(u8, library_path, ":");
+            while (it.next()) |dir|
+                try self.addLibDir(dir);
+        } else |err| switch (err) {
+            error.InvalidUtf8 => {},
+            error.EnvironmentVariableNotFound => {},
+            error.OutOfMemory => |e| return e,
+        }
+        if (!isCrossGuix(allocator)) {
+            const guix_include_paths = [_][]const u8{ "C_INCLUDE_PATH", "CPLUS_INCLUDE_PATH" };
+            for (guix_include_paths) |env_var| {
+                if (process.getEnvVarOwned(allocator, env_var)) |include_path| {
+                    var it = mem.tokenize(u8, include_path, ":");
+                    while (it.next()) |dir|
+                        try self.addIncludeDir(dir);
+                } else |err| switch (err) {
+                    error.InvalidUtf8 => {},
+                    error.EnvironmentVariableNotFound => {},
+                    error.OutOfMemory => |e| return e,
+                }
+            }
+            if (process.getEnvVarOwned(allocator, "LIBRARY_PATH")) |library_path| {
+                var it = mem.tokenize(u8, library_path, ":");
+                while (it.next()) |dir|
+                    try self.addLibDir(dir);
+            } else |err| switch (err) {
+                error.InvalidUtf8 => {},
+                error.EnvironmentVariableNotFound => {},
+                error.OutOfMemory => |e| return e,
+            }
+        }
+        return self;
+    }
     var is_nix = false;
     if (process.getEnvVarOwned(allocator, "NIX_CFLAGS_COMPILE")) |nix_cflags_compile| {
         defer allocator.free(nix_cflags_compile);
@@ -231,3 +277,11 @@ fn appendArray(self: *NativePaths, array: *ArrayList([:0]u8), s: []const u8) !vo
     errdefer array.allocator.free(item);
     try array.append(item);
 }
+
+pub fn isCrossGuix(arena: Allocator) bool {
+    return process.hasEnvVar(arena, "CROSS_LIBRARY_PATH") catch false;
+}
+
+pub fn isGuix(arena: Allocator) bool {
+    return isCrossGuix(arena) or process.hasEnvVar(arena, "LIBRARY_PATH") catch false;
+}
diff --git a/lib/std/zig/system/NativeTargetInfo.zig b/lib/std/zig/system/NativeTargetInfo.zig
index cae45af64b..0c87d49816 100644
--- a/lib/std/zig/system/NativeTargetInfo.zig
+++ b/lib/std/zig/system/NativeTargetInfo.zig
@@ -936,10 +936,27 @@ fn defaultAbiAndDynamicLinker(cpu: Target.Cpu, os: Target.Os, cross_target: Cros
     };
     return NativeTargetInfo{
         .target = target,
-        .dynamic_linker = if (cross_target.dynamic_linker.get() == null)
-            target.standardDynamicLinkerPath()
-        else
-            cross_target.dynamic_linker,
+        .dynamic_linker = if (cross_target.dynamic_linker.get() == null) blk: {
+            var standard_linker = target.standardDynamicLinkerPath();
+            if (standard_linker.get()) |standard_linker_path| {
+                if (builtin.os.tag != .windows and builtin.os.tag != .wasi) {
+                    if (std.os.getenv("CROSS_LIBRARY_PATH") orelse std.os.getenv("LIBRARY_PATH")) |library_path| {
+                        const linker_basename = fs.path.basename(standard_linker_path);
+                        var buffer: [255]u8 = undefined;
+                        var it = mem.tokenize(u8, library_path, ":");
+                        while (it.next()) |dir| {
+                            const linker_fullpath = std.fmt.bufPrint(&buffer, "{s}{s}{s}", .{ dir, fs.path.sep_str, linker_basename }) catch "";
+                            const guix_linker_path = fs.cwd().realpath(linker_fullpath, &buffer) catch "";
+                            if (guix_linker_path.len != 0) {
+                                standard_linker.set(guix_linker_path);
+                                break;
+                            }
+                        }
+                    }
+                }
+            }
+            break :blk standard_linker;
+        } else cross_target.dynamic_linker,
     };
 }
 
diff --git a/src/main.zig b/src/main.zig
index b752c89308..4fb7310a4f 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -2375,7 +2375,8 @@ fn buildOutputType(
             want_native_include_dirs = true;
     }
 
-    if (sysroot == null and cross_target.isNativeOs() and
+    if (std.zig.system.NativePaths.isCrossGuix(arena) or
+        sysroot == null and cross_target.isNativeOs() and
         (system_libs.count() != 0 or want_native_include_dirs))
     {
         const paths = std.zig.system.NativePaths.detect(arena, target_info) catch |err| {
-- 
2.46.0