diff --git a/src/main.zig b/src/main.zig
index cacdb83334f2d5ef8fc029534050c7be579ab8ab..2e83e98fffca17c2df4dfc540343029c20d56db4 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -492,6 +492,7 @@ const usage_build_generic =
     \\    nodelete                     Indicate that the object cannot be deleted from a process
     \\    notext                       Permit read-only relocations in read-only segments
     \\    defs                         Force a fatal error if any undefined symbols remain
+    \\    undefs                       Reverse of -z defs
     \\    origin                       Indicate that the object must have its origin processed
     \\    nocopyreloc                  Disable the creation of copy relocations
     \\    now                          (default) Force all relocations to be processed on load
@@ -1333,6 +1334,8 @@ fn buildOutputType(
                             linker_z_notext = true;
                         } else if (mem.eql(u8, z_arg, "defs")) {
                             linker_z_defs = true;
+                        } else if (mem.eql(u8, z_arg, "undefs")) {
+                            linker_z_defs = false;
                         } else if (mem.eql(u8, z_arg, "origin")) {
                             linker_z_origin = true;
                         } else if (mem.eql(u8, z_arg, "nocopyreloc")) {
@@ -1879,6 +1882,8 @@ fn buildOutputType(
                     linker_gc_sections = true;
                 } else if (mem.eql(u8, arg, "-dead_strip_dylibs")) {
                     dead_strip_dylibs = true;
+                } else if (mem.eql(u8, arg, "--no-undefined")) {
+                    linker_z_defs = true;
                 } else if (mem.eql(u8, arg, "--gc-sections")) {
                     linker_gc_sections = true;
                 } else if (mem.eql(u8, arg, "--no-gc-sections")) {
@@ -1944,6 +1949,8 @@ fn buildOutputType(
                         linker_z_notext = true;
                     } else if (mem.eql(u8, z_arg, "defs")) {
                         linker_z_defs = true;
+                    } else if (mem.eql(u8, z_arg, "undefs")) {
+                        linker_z_defs = false;
                     } else if (mem.eql(u8, z_arg, "origin")) {
                         linker_z_origin = true;
                     } else if (mem.eql(u8, z_arg, "nocopyreloc")) {