diff --git a/lib/std/builtin.zig b/lib/std/builtin.zig
index 4d69a624f9..7b66998dc1 100644
--- a/lib/std/builtin.zig
+++ b/lib/std/builtin.zig
@@ -751,9 +751,18 @@ else
 /// therefore must be kept in sync with the compiler implementation.
 pub fn default_panic(msg: []const u8, error_return_trace: ?*StackTrace) noreturn {
     @setCold(true);
+
     // Until self-hosted catches up with stage1 language features, we have a simpler
     // default panic function:
-    if (builtin.zig_backend != .stage1 and builtin.zig_backend != .stage2_llvm) {
+    if ((builtin.zig_backend == .stage2_llvm and builtin.link_libc) or
+        builtin.zig_backend == .stage2_c or
+        builtin.zig_backend == .stage2_wasm or
+        builtin.zig_backend == .stage2_arm or
+        builtin.zig_backend == .stage2_aarch64 or
+        builtin.zig_backend == .stage2_x86_64 or
+        builtin.zig_backend == .stage2_x86 or
+        builtin.zig_backend == .stage2_riscv64)
+    {
         while (true) {
             @breakpoint();
         }
diff --git a/lib/std/c/linux.zig b/lib/std/c/linux.zig
index a0f90f563b..5f96fe3fe0 100644
--- a/lib/std/c/linux.zig
+++ b/lib/std/c/linux.zig
@@ -263,7 +263,11 @@ pub extern "c" fn inotify_rm_watch(fd: fd_t, wd: c_int) c_int;
 /// See std.elf for constants for this
 pub extern "c" fn getauxval(__type: c_ulong) c_ulong;
 
-pub const dl_iterate_phdr_callback = fn (info: *dl_phdr_info, size: usize, data: ?*anyopaque) callconv(.C) c_int;
+pub const dl_iterate_phdr_callback = switch (builtin.zig_backend) {
+    .stage1 => fn (info: *dl_phdr_info, size: usize, data: ?*anyopaque) callconv(.C) c_int,
+    else => *const fn (info: *dl_phdr_info, size: usize, data: ?*anyopaque) callconv(.C) c_int,
+};
+
 pub extern "c" fn dl_iterate_phdr(callback: dl_iterate_phdr_callback, data: ?*anyopaque) c_int;
 
 pub extern "c" fn sigaltstack(ss: ?*stack_t, old_ss: ?*stack_t) c_int;
diff --git a/src/Sema.zig b/src/Sema.zig
index 28110efc83..8ac994a543 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -6231,6 +6231,10 @@ fn funcCommon(
             comptime_params[i] = param.is_comptime or
                 try sema.typeRequiresComptime(block, param_src, param.ty);
             is_generic = is_generic or comptime_params[i] or param.ty.tag() == .generic_poison;
+            if (is_extern and is_generic) {
+                // TODO add note: function is generic because of this parameter
+                return sema.fail(block, param_src, "extern function cannot be generic", .{});
+            }
         }
 
         is_generic = is_generic or