diff --git a/libc/include/link.h b/libc/include/link.h
index 341fbf1..cb8e139 100644
--- a/libc/include/link.h
+++ b/libc/include/link.h
@@ -33,7 +33,11 @@
 
 __BEGIN_DECLS
 
-#define ElfW(type) Elf_##type
+#if __LP64__
+#define ElfW(type) Elf64_ ## type
+#else
+#define ElfW(type) Elf32_ ## type
+#endif
 
 struct dl_phdr_info {
   ElfW(Addr) dlpi_addr;
@@ -42,13 +46,35 @@
   ElfW(Half) dlpi_phnum;
 };
 
-int dl_iterate_phdr(int (*cb)(struct dl_phdr_info*, size_t, void*), void*);
+int dl_iterate_phdr(int (*)(struct dl_phdr_info*, size_t, void*), void*);
 
 #ifdef __arm__
 typedef long unsigned int* _Unwind_Ptr;
-_Unwind_Ptr dl_unwind_find_exidx(_Unwind_Ptr pc, int* pcount);
+_Unwind_Ptr dl_unwind_find_exidx(_Unwind_Ptr, int*);
 #endif
 
+/* Used by the dynamic linker to communicate with the debugger. */
+struct link_map {
+  ElfW(Addr) l_addr;
+  char* l_name;
+  ElfW(Dyn)* l_ld;
+  struct link_map* l_next;
+  struct link_map* l_prev;
+};
+
+/* Used by the dynamic linker to communicate with the debugger. */
+struct r_debug {
+  int32_t r_version;
+  struct link_map* r_map;
+  ElfW(Addr) r_brk;
+  enum {
+    RT_CONSISTENT,
+    RT_ADD,
+    RT_DELETE
+  } r_state;
+  ElfW(Addr) r_ldbase;
+};
+
 __END_DECLS
 
 #endif /* _LINK_H_ */
diff --git a/linker/linker.cpp b/linker/linker.cpp
index 9bc9afe..2058050 100755
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -187,17 +187,17 @@
  */
 extern "C" void __attribute__((noinline)) __attribute__((visibility("default"))) rtld_db_dlactivity();
 
-static r_debug _r_debug = {1, NULL, &rtld_db_dlactivity, RT_CONSISTENT, 0};
-static link_map_t* r_debug_tail = 0;
+static r_debug _r_debug = {1, NULL, reinterpret_cast<uintptr_t>(&rtld_db_dlactivity), r_debug::RT_CONSISTENT, 0};
+static link_map* r_debug_tail = 0;
 
 static pthread_mutex_t gDebugMutex = PTHREAD_MUTEX_INITIALIZER;
 
-static void insert_soinfo_into_debug_map(soinfo * info) {
+static void insert_soinfo_into_debug_map(soinfo* info) {
     // Copy the necessary fields into the debug structure.
-    link_map_t* map = &(info->link_map);
+    link_map* map = &(info->link_map_head);
     map->l_addr = info->load_bias;
     map->l_name = (char*) info->name;
-    map->l_ld = (uintptr_t)info->dynamic;
+    map->l_ld = info->dynamic;
 
     /* Stick the new library at the end of the list.
      * gdb tends to care more about libc than it does
@@ -217,7 +217,7 @@
 }
 
 static void remove_soinfo_from_debug_map(soinfo* info) {
-    link_map_t* map = &(info->link_map);
+    link_map* map = &(info->link_map_head);
 
     if (r_debug_tail == map) {
         r_debug_tail = map->l_prev;
@@ -239,12 +239,12 @@
 
     ScopedPthreadMutexLocker locker(&gDebugMutex);
 
-    _r_debug.r_state = RT_ADD;
+    _r_debug.r_state = r_debug::RT_ADD;
     rtld_db_dlactivity();
 
     insert_soinfo_into_debug_map(info);
 
-    _r_debug.r_state = RT_CONSISTENT;
+    _r_debug.r_state = r_debug::RT_CONSISTENT;
     rtld_db_dlactivity();
 }
 
@@ -256,20 +256,20 @@
 
     ScopedPthreadMutexLocker locker(&gDebugMutex);
 
-    _r_debug.r_state = RT_DELETE;
+    _r_debug.r_state = r_debug::RT_DELETE;
     rtld_db_dlactivity();
 
     remove_soinfo_from_debug_map(info);
 
-    _r_debug.r_state = RT_CONSISTENT;
+    _r_debug.r_state = r_debug::RT_CONSISTENT;
     rtld_db_dlactivity();
 }
 
 void notify_gdb_of_libraries() {
-    _r_debug.r_state = RT_ADD;
-    rtld_db_dlactivity();
-    _r_debug.r_state = RT_CONSISTENT;
-    rtld_db_dlactivity();
+  _r_debug.r_state = r_debug::RT_ADD;
+  rtld_db_dlactivity();
+  _r_debug.r_state = r_debug::RT_CONSISTENT;
+  rtld_db_dlactivity();
 }
 
 static bool ensure_free_list_non_empty() {
@@ -439,8 +439,8 @@
     int rv = 0;
     for (soinfo* si = solist; si != NULL; si = si->next) {
         dl_phdr_info dl_info;
-        dl_info.dlpi_addr = si->link_map.l_addr;
-        dl_info.dlpi_name = si->link_map.l_name;
+        dl_info.dlpi_addr = si->link_map_head.l_addr;
+        dl_info.dlpi_name = si->link_map_head.l_name;
         dl_info.dlpi_phdr = si->phdr;
         dl_info.dlpi_phnum = si->phnum;
         rv = cb(&dl_info, sizeof(dl_phdr_info), data);
@@ -2038,7 +2038,7 @@
 
     /* bootstrap the link map, the main exe always needs to be first */
     si->flags |= FLAG_EXE;
-    link_map_t* map = &(si->link_map);
+    link_map* map = &(si->link_map_head);
 
     map->l_addr = 0;
     map->l_name = args.argv[0];
diff --git a/linker/linker.h b/linker/linker.h
index 972050f..654ee5f 100644
--- a/linker/linker.h
+++ b/linker/linker.h
@@ -61,31 +61,6 @@
 // itself at the start of a page.
 #define PAGE_END(x)    PAGE_START((x) + (PAGE_SIZE-1))
 
-// Magic shared structures that GDB knows about.
-
-struct link_map_t {
-  uintptr_t l_addr;
-  char*  l_name;
-  uintptr_t l_ld;
-  link_map_t* l_next;
-  link_map_t* l_prev;
-};
-
-// Values for r_debug->state
-enum {
-  RT_CONSISTENT,
-  RT_ADD,
-  RT_DELETE
-};
-
-struct r_debug {
-  int32_t r_version;
-  link_map_t* r_map;
-  void (*r_brk)(void);
-  int32_t r_state;
-  uintptr_t r_ldbase;
-};
-
 #define FLAG_LINKED     0x00000001
 #define FLAG_EXE        0x00000004 // The main executable
 #define FLAG_LINKER     0x00000010 // The linker itself
@@ -172,7 +147,7 @@
 #endif
 
   size_t ref_count;
-  link_map_t link_map;
+  link_map link_map_head;
 
   bool constructors_called;