zld: permit system static libs

This commits permits passing in static archives using the system
lib flag `-la`. With this commit, `zig ld` will now look firstly for
a dynamic library (which always takes precedence), and will fall back
on `liba.a` if the dylib is not found. The static archive is searched
for in the system lib search dirs like the dylibs.

5 files changed, 38 insertions, 0 deletions

diff --git a/test/standalone.zig b/test/standalone.zig
index e1236d448b..9dd849ef88 100644
--- a/test/standalone.zig
+++ b/test/standalone.zig
@@ -14,6 +14,7 @@ pub fn addCases(cases: *tests.StandaloneContext) void {
     cases.addBuildFile("test/standalone/global_linkage/build.zig");
     cases.addBuildFile("test/standalone/static_c_lib/build.zig");
     cases.addBuildFile("test/standalone/link_interdependent_static_c_libs/build.zig");
+    cases.addBuildFile("test/standalone/link_static_lib_as_system_lib/build.zig");
     cases.addBuildFile("test/standalone/issue_339/build.zig");
     cases.addBuildFile("test/standalone/issue_794/build.zig");
     cases.addBuildFile("test/standalone/issue_5825/build.zig");
diff --git a/test/standalone/link_static_lib_as_system_lib/a.c b/test/standalone/link_static_lib_as_system_lib/a.c
new file mode 100644
index 0000000000..ee9da97a3a
--- /dev/null
+++ b/test/standalone/link_static_lib_as_system_lib/a.c
@@ -0,0 +1,4 @@
+#include "a.h"
+int32_t add(int32_t a, int32_t b) {
+    return a + b;
+}
diff --git a/test/standalone/link_static_lib_as_system_lib/a.h b/test/standalone/link_static_lib_as_system_lib/a.h
new file mode 100644
index 0000000000..7b45d54d56
--- /dev/null
+++ b/test/standalone/link_static_lib_as_system_lib/a.h
@@ -0,0 +1,2 @@
+#include <stdint.h>
+int32_t add(int32_t a, int32_t b);
diff --git a/test/standalone/link_static_lib_as_system_lib/build.zig b/test/standalone/link_static_lib_as_system_lib/build.zig
new file mode 100644
index 0000000000..f951b68a8c
--- /dev/null
+++ b/test/standalone/link_static_lib_as_system_lib/build.zig
@@ -0,0 +1,23 @@
+const std = @import("std");
+const Builder = std.build.Builder;
+
+pub fn build(b: *Builder) void {
+    const mode = b.standardReleaseOptions();
+
+    const lib_a = b.addStaticLibrary("a", null);
+    lib_a.addCSourceFile("a.c", &[_][]const u8{});
+    lib_a.setBuildMode(mode);
+    lib_a.addIncludeDir(".");
+    lib_a.install();
+
+    const test_exe = b.addTest("main.zig");
+    test_exe.setBuildMode(mode);
+    test_exe.linkSystemLibrary("a"); // force linking liba.a as -la
+    test_exe.addSystemIncludeDir(".");
+    const search_path = std.fs.path.join(b.allocator, &[_][]const u8{ b.install_path, "lib" }) catch unreachable;
+    test_exe.addLibPath(search_path);
+
+    const test_step = b.step("test", "Test it");
+    test_step.dependOn(b.getInstallStep());
+    test_step.dependOn(&test_exe.step);
+}
diff --git a/test/standalone/link_static_lib_as_system_lib/main.zig b/test/standalone/link_static_lib_as_system_lib/main.zig
new file mode 100644
index 0000000000..0b9c46217f
--- /dev/null
+++ b/test/standalone/link_static_lib_as_system_lib/main.zig
@@ -0,0 +1,8 @@
+const std = @import("std");
+const expect = std.testing.expect;
+const c = @cImport(@cInclude("a.h"));
+
+test "import C add" {
+    const result = c.add(2, 1);
+    try expect(result == 3);
+}