Remove 32-bit assumptions from the ELF code.

Change-Id: I2c1f3d34c33685799aade8866eec44479ff9f963
diff --git a/libc/private/KernelArgumentBlock.h b/libc/private/KernelArgumentBlock.h
index 14eca06..105965e 100644
--- a/libc/private/KernelArgumentBlock.h
+++ b/libc/private/KernelArgumentBlock.h
@@ -30,7 +30,7 @@
 class KernelArgumentBlock {
  public:
   KernelArgumentBlock(void* raw_args) {
-    uint32_t* args = reinterpret_cast<uint32_t*>(raw_args);
+    uintptr_t* args = reinterpret_cast<uintptr_t*>(raw_args);
     argc = static_cast<int>(*args);
     argv = reinterpret_cast<char**>(args + 1);
     envp = argv + argc + 1;
@@ -43,14 +43,14 @@
     }
     ++p; // Skip second NULL;
 
-    auxv = reinterpret_cast<Elf32_auxv_t*>(p);
+    auxv = reinterpret_cast<Elf_auxv_t*>(p);
   }
 
   // Similar to ::getauxval but doesn't require the libc global variables to be set up,
   // so it's safe to call this really early on. This function also lets you distinguish
   // between the inability to find the given type and its value just happening to be 0.
   unsigned long getauxval(unsigned long type, bool* found_match = NULL) {
-    for (Elf32_auxv_t* v = auxv; v->a_type != AT_NULL; ++v) {
+    for (Elf_auxv_t* v = auxv; v->a_type != AT_NULL; ++v) {
       if (v->a_type == type) {
         if (found_match != NULL) {
             *found_match = true;
@@ -67,7 +67,7 @@
   int argc;
   char** argv;
   char** envp;
-  Elf32_auxv_t* auxv;
+  Elf_auxv_t* auxv;
 
   abort_msg_t** abort_message_ptr;