From 5ac91794cce8bd53916a378815be01e4365d53d9 Mon Sep 17 00:00:00 2001
From: Isaac Freund <ifreund@ifreund.xyz>
Date: Mon, 10 May 2021 21:29:20 +0200
Subject: [PATCH] stage2: use system libc when targeting the native OS/ABI

Currently zig will always try to build its own libc and compile against
that. This of course makes sense for cross-compilation, but can cause
problems when targeting the native OS/ABI.

For example, if the system uses a newer glibc version than zig ships
zig will fall back to using the newest version it does ship. However
this causes linking system libraries to fail as they are built against a
different glibc version than the zig code is built against.

To remedy this, simply default to linking the system libc when targeting
the native OS/ABI.
---
 src/Compilation.zig | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/Compilation.zig b/src/Compilation.zig
index 87d4c4c41e..71df776855 100644
--- a/src/Compilation.zig
+++ b/src/Compilation.zig
@@ -848,7 +848,7 @@ pub fn create(gpa: *Allocator, options: InitOptions) !*Compilation {
             arena,
             options.zig_lib_directory.path.?,
             options.target,
-            options.is_native_os,
+            options.is_native_abi,
             link_libc,
             options.libc_installation,
         );
@@ -2885,7 +2885,7 @@ fn detectLibCIncludeDirs(
     arena: *Allocator,
     zig_lib_dir: []const u8,
     target: Target,
-    is_native_os: bool,
+    is_native_abi: bool,
     link_libc: bool,
     libc_installation: ?*const LibCInstallation,
 ) !LibCDirs {
@@ -2900,6 +2900,12 @@ fn detectLibCIncludeDirs(
         return detectLibCFromLibCInstallation(arena, target, lci);
     }
 
+    if (is_native_abi) {
+        const libc = try arena.create(LibCInstallation);
+        libc.* = try LibCInstallation.findNative(.{ .allocator = arena });
+        return detectLibCFromLibCInstallation(arena, target, libc);
+    }
+
     if (target_util.canBuildLibC(target)) {
         const generic_name = target_util.libCGenericName(target);
         // Some architectures are handled by the same set of headers.
@@ -2950,12 +2956,6 @@ fn detectLibCIncludeDirs(
         };
     }
 
-    if (is_native_os) {
-        const libc = try arena.create(LibCInstallation);
-        libc.* = try LibCInstallation.findNative(.{ .allocator = arena });
-        return detectLibCFromLibCInstallation(arena, target, libc);
-    }
-
     return LibCDirs{
         .libc_include_dir_list = &[0][]u8{},
         .libc_installation = null,