[libc] Pull crt0 out into its own module

Sorta. crt0 is a separate module as far as bonnibel is concerned, but it's
still part of the libc module file.

src/libraries/libc/arch/amd64/crt/crt0.s

@@ -1,10 +1,18 @@
-%include "util/got.inc"
+extern _GLOBAL_OFFSET_TABLE_
 
 extern main
 extern exit
 extern __init_libj6
 extern __init_libc
 
+; Put the address of the given symbol in rax
+; This macro is the same as in util/got.inc,
+; but crt0 can't have a dep on libutil
+%macro lookup_GOT 1
+    lea rax, [rel _GLOBAL_OFFSET_TABLE_]
+    mov rax, [rax + %1 wrt ..got]
+%endmacro
+
 global _start:function weak (_libc_crt0_start.end - _libc_crt0_start)
 global _libc_crt0_start:function (_libc_crt0_start.end - _libc_crt0_start)
 

src/libraries/libc/arch/amd64/crt/init.cpp

@@ -1,38 +0,0 @@
-#include <stddef.h>
-
-using cb = void (*)(void);
-extern cb __preinit_array_start;
-extern cb __preinit_array_end;
-extern cb __init_array_start;
-extern cb __init_array_end;
-
-namespace {
-
-void
-run_ctor_list(cb *array, cb *end)
-{
-    if (!array || !end)
-        return;
-
-    size_t i = 0;
-    while (true) {
-        const cb &ctor = array[i++];
-        if (&ctor == end) return;
-        if (ctor) ctor();
-    }
-}
-
-void
-run_global_ctors()
-{
-    run_ctor_list(&__preinit_array_start, &__preinit_array_end);
-    run_ctor_list(&__init_array_start, &__init_array_end);
-}
-
-} // namespace
-
-extern "C"
-void __init_libc()
-{
-    run_global_ctors();
-}

src/libraries/libc/arch/amd64/crt/libdl.cpp

@@ -1,7 +0,0 @@
-
-extern "C" {
-    // Stub out these libdl functions for libunwind until
-    // we have a real libdl
-    int dladdr(const void *, void *) { return 0; }
-    int dl_iterate_phdr(void *, void *) { return 0; }
-}