lib: add support for omitting soname

This commit adds the `soname` option for `Build.Module` and
`OverlayOptions`. This controls whether `-fsoname` or `-fno-soname` is
passed to the linker.

This is needed to implement the new test in
#19818

Author: a-khabarov

lib/std/Build/Module.zig

@@ -18,6 +18,7 @@ frameworks: std.StringArrayHashMapUnmanaged(LinkFrameworkOptions),
 link_objects: std.ArrayListUnmanaged(LinkObject),
 
 strip: ?bool,
+soname: ?bool,
 unwind_tables: ?std.builtin.UnwindTables,
 single_threaded: ?bool,
 stack_protector: ?bool,
@@ -247,6 +248,7 @@ pub const CreateOptions = struct {
     link_libcpp: ?bool = null,
     single_threaded: ?bool = null,
     strip: ?bool = null,
+    soname: ?bool = null,
     unwind_tables: ?std.builtin.UnwindTables = null,
     dwarf_format: ?std.dwarf.Format = null,
     code_model: std.builtin.CodeModel = .default,
@@ -296,6 +298,7 @@ pub fn init(
                 .frameworks = .{},
                 .link_objects = .{},
                 .strip = options.strip,
+                .soname = options.soname,
                 .unwind_tables = options.unwind_tables,
                 .single_threaded = options.single_threaded,
                 .stack_protector = options.stack_protector,
@@ -545,6 +548,7 @@ pub fn appendZigProcessFlags(
     const b = m.owner;
 
     try addFlag(zig_args, m.strip, "-fstrip", "-fno-strip");
+    try addFlag(zig_args, m.soname, "-fsoname", "-fno-soname");
     try addFlag(zig_args, m.single_threaded, "-fsingle-threaded", "-fno-single-threaded");
     try addFlag(zig_args, m.stack_check, "-fstack-check", "-fno-stack-check");
     try addFlag(zig_args, m.stack_protector, "-fstack-protector", "-fno-stack-protector");

test/link/link.zig

@@ -44,6 +44,7 @@ const OverlayOptions = struct {
     zig_source_bytes: ?[]const u8 = null,
     pic: ?bool = null,
     strip: ?bool = null,
+    soname: ?bool = null,
 };
 
 pub fn addExecutable(b: *std.Build, base: Options, overlay: OverlayOptions) *Compile {
@@ -97,6 +98,7 @@ fn createModule(b: *Build, base: Options, overlay: OverlayOptions) *Build.Module
         },
         .pic = overlay.pic,
         .strip = if (base.strip) |s| s else overlay.strip,
+        .soname = overlay.soname,
     });
 
     if (overlay.objcpp_source_bytes) |bytes| {