res_search: fix for aarch64

On linux_aarch64 `res_search` is `__res_search@GLIBC_2.17`, which is
different from the x86_64 counterpart `__res_search@GLIBC_2.2.5`.

Also fix tests.

test/cgo/BUILD

@@ -6,7 +6,6 @@ go_library(
     name = "cgo_lib",
     srcs = ["cgo.go"],
     cgo = True,
-    clinkopts = ["-lresolv"],
     importpath = "git.sr.ht/~motiejus/bazel-zig-cc/test/cgo",
     visibility = ["//visibility:private"],
 )

test/cgo/cgo.go

@@ -1,13 +1,8 @@
 package main
 
-// #define _FILE_OFFSET_BITS 64
-// #include <unistd.h>
-// #include <fcntl.h>
 // #include <stdio.h>
-// #include <resolv.h>
 // char* hello() { return "hello, world"; }
-// void phello() { printf("%s, your lucky numbers are %p and %p\n", hello(), fcntl, res_search); }
-// #cgo LDFLAGS: -lresolv
+// void phello() { printf("%s\n", hello()); }
 import "C"
 
 func main() {

test/glibc_hacks/BUILD

@@ -0,0 +1,22 @@
+load("@bazel-zig-cc//rules:platform.bzl", "platform_binary")
+
+cc_binary(
+    name = "main",
+    srcs = ["main.c"],
+)
+
+[
+    (
+        platform_binary(
+            name = "main_{}".format(name),
+            src = "main",
+            platform = platform,
+        ),
+    )
+    for name, platform in [
+        ("linux_amd64_musl", "//libc_aware/platform:linux_amd64_musl"),
+        ("linux_amd64_gnu.2.19", "//libc_aware/platform:linux_amd64_gnu.2.19"),
+        ("linux_amd64_gnu.2.28", "//libc_aware/platform:linux_amd64_gnu.2.28"),
+        ("linux_arm64_musl", "//libc_aware/platform:linux_arm64_musl"),
+    ]
+]

test/glibc_hacks/main.c

@@ -0,0 +1,13 @@
+// This file tests that problematic functions (glibc-hacks) work.
+// Also see https://github.com/ziglang/zig/issues/9485
+
+#define _FILE_OFFSET_BITS 64
+#include <unistd.h>
+#include <fcntl.h>
+#include <resolv.h>
+#include <stdio.h>
+
+int main() {
+    printf("Your lucky numbers are %p and %p\n", fcntl, res_search);
+    return 0;
+}

toolchain/defs.bzl

@@ -208,9 +208,12 @@ def _zig_repository_impl(repository_ctx):
     fcntl_hack = _glibc_hack("fcntl64", "fcntl@GLIBC_2.2.5")
     repository_ctx.file("glibc-hacks/fcntl.map", content = fcntl_hack.mapfile)
     repository_ctx.file("glibc-hacks/fcntl.h", content = fcntl_hack.header)
-    res_search_hack = _glibc_hack("res_search", "__res_search@GLIBC_2.2.5")
-    repository_ctx.file("glibc-hacks/res_search.map", content = res_search_hack.mapfile)
-    repository_ctx.file("glibc-hacks/res_search.h", content = res_search_hack.header)
+    res_search_amd64 = _glibc_hack("res_search", "__res_search@GLIBC_2.2.5")
+    repository_ctx.file("glibc-hacks/res_search-amd64.map", content = res_search_amd64.mapfile)
+    repository_ctx.file("glibc-hacks/res_search-amd64.h", content = res_search_amd64.header)
+    res_search_arm64 = _glibc_hack("res_search", "__res_search@GLIBC_2.17")
+    repository_ctx.file("glibc-hacks/res_search-arm64.map", content = res_search_arm64.mapfile)
+    repository_ctx.file("glibc-hacks/res_search-arm64.h", content = res_search_arm64.header)
 
 zig_repository = repository_rule(
     attrs = {

toolchain/private/defs.bzl

@@ -128,8 +128,8 @@ def _target_linux_gnu(gocpu, zigcpu, glibc_version):
         compiler_extra_includes.append("glibc-hacks/fcntl.h")
         linker_version_scripts.append("glibc-hacks/fcntl.map")
     if glibc_version < "2.34":
-        compiler_extra_includes.append("glibc-hacks/res_search.h")
-        linker_version_scripts.append("glibc-hacks/res_search.map")
+        compiler_extra_includes.append("glibc-hacks/res_search-{}.h".format(gocpu))
+        linker_version_scripts.append("glibc-hacks/res_search-{}.map".format(gocpu))
 
     return struct(
         gotarget = "linux_{}_{}".format(gocpu, glibc_suffix),