Remove the ___ hack.

Plain __ for generated syscalls didn't mean it was a hidden symbol, it
just meant "please don't use this". We added ___ to signify that a
hidden symbol should be generated, but then we added the map files
anyway so you now have to explicitly export symbols. Given that, this
convention serves no particular purpose so we may as well just use the
nicer names have everything look the same.

Test: treehugger
Change-Id: If424e17a49c36f4be545f5d283c4561a6ea9c7ea
diff --git a/libc/bionic/mremap.cpp b/libc/bionic/mremap.cpp
index 896ccef..a4e5323 100644
--- a/libc/bionic/mremap.cpp
+++ b/libc/bionic/mremap.cpp
@@ -34,7 +34,7 @@
 
 #include "private/bionic_macros.h"
 
-extern "C" void* ___mremap(void*, size_t, size_t, int, void*);
+extern "C" void* __mremap(void*, size_t, size_t, int, void*);
 
 void* mremap(void* old_address, size_t old_size, size_t new_size, int flags, ...) {
   // prevent allocations large enough for `end - start` to overflow
@@ -53,5 +53,5 @@
     new_address = va_arg(ap, void*);
     va_end(ap);
   }
-  return ___mremap(old_address, old_size, new_size, flags, new_address);
+  return __mremap(old_address, old_size, new_size, flags, new_address);
 }