fix ziglang#3237: resolve undefined symbol _DllMainCRTStartup

Author: zhaozg

src/link/Coff.zig

@@ -811,7 +811,7 @@ fn linkWithLLD(self: *Coff, comp: *Compilation) !void {
     const is_lib = self.base.options.output_mode == .Lib;
     const is_dyn_lib = self.base.options.link_mode == .Dynamic and is_lib;
     const is_exe_or_dyn_lib = is_dyn_lib or self.base.options.output_mode == .Exe;
-    const link_in_crt = self.base.options.link_libc and self.base.options.output_mode == .Exe;
+    const link_in_crt = self.base.options.link_libc and is_exe_or_dyn_lib;
     const target = self.base.options.target;
 
     // See link/Elf.zig for comments on how this mechanism works.
@@ -1054,6 +1054,7 @@ fn linkWithLLD(self: *Coff, comp: *Compilation) !void {
 
                         if (is_dyn_lib) {
                             try argv.append(try comp.get_libc_crt_file(arena, "dllcrt2.o"));
+                            try argv.append("-ALTERNATENAME:_DllMainCRTStartup=DllMainCRTStartup");
                         } else {
                             try argv.append(try comp.get_libc_crt_file(arena, "crt2.o"));
                         }