diff --git a/base/include/android-base/endian.h b/base/include/android-base/endian.h
index 10efaa3..2d0f614 100644
--- a/base/include/android-base/endian.h
+++ b/base/include/android-base/endian.h
@@ -18,6 +18,9 @@
 
 /* A cross-platform equivalent of bionic's <sys/endian.h>. */
 
+/* For __BIONIC__ and __GLIBC__ */
+#include <sys/cdefs.h>
+
 #if defined(__BIONIC__)
 
 #include <sys/endian.h>
@@ -38,6 +41,9 @@
 #define betoh16(x) be16toh(x)
 #define betoh32(x) be32toh(x)
 #define betoh64(x) be64toh(x)
+#define letoh16(x) le16toh(x)
+#define letoh32(x) le32toh(x)
+#define letoh64(x) le64toh(x)
 
 #else
 
@@ -45,10 +51,8 @@
 /* macOS has some of the basics. */
 #include <sys/_endian.h>
 #else
-/* Windows really has nothing. */
-#define LITTLE_ENDIAN __LITTLE_ENDIAN
-#define BIG_ENDIAN __BIG_ENDIAN
-#define BYTE_ORDER __BYTE_ORDER
+/* Windows has even less. */
+#include <sys/param.h>
 #define htons(x) __builtin_bswap16(x)
 #define htonl(x) __builtin_bswap32(x)
 #define ntohs(x) __builtin_bswap16(x)
diff --git a/base/include/android-base/mapped_file.h b/base/include/android-base/mapped_file.h
index 2ab49ab..6a19f1b 100644
--- a/base/include/android-base/mapped_file.h
+++ b/base/include/android-base/mapped_file.h
@@ -28,15 +28,17 @@
 #include <windows.h>
 #define PROT_READ 1
 #define PROT_WRITE 2
+using os_handle = HANDLE;
 #else
 #include <sys/mman.h>
+using os_handle = int;
 #endif
 
 namespace android {
 namespace base {
 
 /**
- * A region of a file mapped into memory, also known as MmapFile.
+ * A region of a file mapped into memory (for grepping: also known as MmapFile or file mapping).
  */
 class MappedFile {
  public:
@@ -49,16 +51,33 @@
                                             int prot);
 
   /**
+   * Same thing, but using the raw OS file handle instead of a CRT wrapper.
+   */
+  static MappedFile FromOsHandle(os_handle h, off64_t offset, size_t length, int prot);
+
+  /**
    * Removes the mapping.
    */
   ~MappedFile();
 
-  char* data() { return base_ + offset_; }
-  size_t size() { return size_; }
+  /**
+   * Not copyable but movable.
+   */
+  MappedFile(MappedFile&& other);
+  MappedFile& operator=(MappedFile&& other);
+
+  char* data() const { return base_ + offset_; }
+  size_t size() const { return size_; }
+
+  bool isValid() const { return base_ != nullptr; }
+
+  explicit operator bool() const { return isValid(); }
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(MappedFile);
 
+  void Close();
+
   char* base_;
   size_t size_;
 
diff --git a/base/mapped_file.cpp b/base/mapped_file.cpp
index f60de56..862b73b 100644
--- a/base/mapped_file.cpp
+++ b/base/mapped_file.cpp
@@ -16,13 +16,15 @@
 
 #include "android-base/mapped_file.h"
 
-#include <errno.h>
+#include <utility>
 
-#include "android-base/unique_fd.h"
+#include <errno.h>
 
 namespace android {
 namespace base {
 
+static constexpr char kEmptyBuffer[] = {'0'};
+
 static off64_t InitPageSize() {
 #if defined(_WIN32)
   SYSTEM_INFO si;
@@ -35,51 +37,86 @@
 
 std::unique_ptr<MappedFile> MappedFile::FromFd(borrowed_fd fd, off64_t offset, size_t length,
                                                int prot) {
-  static off64_t page_size = InitPageSize();
+#if defined(_WIN32)
+  auto file =
+      FromOsHandle(reinterpret_cast<HANDLE>(_get_osfhandle(fd.get())), offset, length, prot);
+#else
+  auto file = FromOsHandle(fd.get(), offset, length, prot);
+#endif
+  return file ? std::make_unique<MappedFile>(std::move(file)) : std::unique_ptr<MappedFile>{};
+}
+
+MappedFile MappedFile::FromOsHandle(os_handle h, off64_t offset, size_t length, int prot) {
+  static const off64_t page_size = InitPageSize();
   size_t slop = offset % page_size;
   off64_t file_offset = offset - slop;
   off64_t file_length = length + slop;
 
 #if defined(_WIN32)
-  HANDLE handle =
-      CreateFileMapping(reinterpret_cast<HANDLE>(_get_osfhandle(fd.get())), nullptr,
-                        (prot & PROT_WRITE) ? PAGE_READWRITE : PAGE_READONLY, 0, 0, nullptr);
+  HANDLE handle = CreateFileMappingW(
+      h, nullptr, (prot & PROT_WRITE) ? PAGE_READWRITE : PAGE_READONLY, 0, 0, nullptr);
   if (handle == nullptr) {
     // http://b/119818070 "app crashes when reading asset of zero length".
     // Return a MappedFile that's only valid for reading the size.
-    if (length == 0) {
-      return std::unique_ptr<MappedFile>(new MappedFile{nullptr, 0, 0, nullptr});
+    if (length == 0 && ::GetLastError() == ERROR_FILE_INVALID) {
+      return MappedFile{const_cast<char*>(kEmptyBuffer), 0, 0, nullptr};
     }
-    return nullptr;
+    return MappedFile(nullptr, 0, 0, nullptr);
   }
   void* base = MapViewOfFile(handle, (prot & PROT_WRITE) ? FILE_MAP_ALL_ACCESS : FILE_MAP_READ, 0,
                              file_offset, file_length);
   if (base == nullptr) {
     CloseHandle(handle);
-    return nullptr;
+    return MappedFile(nullptr, 0, 0, nullptr);
   }
-  return std::unique_ptr<MappedFile>(
-      new MappedFile{static_cast<char*>(base), length, slop, handle});
+  return MappedFile{static_cast<char*>(base), length, slop, handle};
 #else
-  void* base = mmap(nullptr, file_length, prot, MAP_SHARED, fd.get(), file_offset);
+  void* base = mmap(nullptr, file_length, prot, MAP_SHARED, h, file_offset);
   if (base == MAP_FAILED) {
     // http://b/119818070 "app crashes when reading asset of zero length".
     // mmap fails with EINVAL for a zero length region.
     if (errno == EINVAL && length == 0) {
-      return std::unique_ptr<MappedFile>(new MappedFile{nullptr, 0, 0});
+      return MappedFile{const_cast<char*>(kEmptyBuffer), 0, 0};
     }
-    return nullptr;
+    return MappedFile(nullptr, 0, 0);
   }
-  return std::unique_ptr<MappedFile>(new MappedFile{static_cast<char*>(base), length, slop});
+  return MappedFile{static_cast<char*>(base), length, slop};
 #endif
 }
 
+MappedFile::MappedFile(MappedFile&& other)
+    : base_(std::exchange(other.base_, nullptr)),
+      size_(std::exchange(other.size_, 0)),
+      offset_(std::exchange(other.offset_, 0))
+#ifdef _WIN32
+      ,
+      handle_(std::exchange(other.handle_, nullptr))
+#endif
+{
+}
+
+MappedFile& MappedFile::operator=(MappedFile&& other) {
+  Close();
+  base_ = std::exchange(other.base_, nullptr);
+  size_ = std::exchange(other.size_, 0);
+  offset_ = std::exchange(other.offset_, 0);
+#ifdef _WIN32
+  handle_ = std::exchange(other.handle_, nullptr);
+#endif
+  return *this;
+}
+
 MappedFile::~MappedFile() {
+  Close();
+}
+
+void MappedFile::Close() {
 #if defined(_WIN32)
-  if (base_ != nullptr) UnmapViewOfFile(base_);
+  if (base_ != nullptr && size_ != 0) UnmapViewOfFile(base_);
   if (handle_ != nullptr) CloseHandle(handle_);
+  handle_ = nullptr;
 #else
-  if (base_ != nullptr) munmap(base_, size_ + offset_);
+  if (base_ != nullptr && size_ != 0) munmap(base_, size_ + offset_);
 #endif
 
   base_ = nullptr;
diff --git a/base/mapped_file_test.cpp b/base/mapped_file_test.cpp
index cfde73c..3629108 100644
--- a/base/mapped_file_test.cpp
+++ b/base/mapped_file_test.cpp
@@ -44,5 +44,8 @@
   ASSERT_TRUE(tf.fd != -1);
 
   auto m = android::base::MappedFile::FromFd(tf.fd, 4096, 0, PROT_READ);
-  ASSERT_EQ(0u, m->size());
+  ASSERT_NE(nullptr, m);
+  EXPECT_TRUE((bool)*m);
+  EXPECT_EQ(0u, m->size());
+  EXPECT_NE(nullptr, m->data());
 }
diff --git a/libnativeloader/library_namespaces.h b/libnativeloader/library_namespaces.h
index 84cabde..7b3efff 100644
--- a/libnativeloader/library_namespaces.h
+++ b/libnativeloader/library_namespaces.h
@@ -38,7 +38,7 @@
 // object for a given ClassLoader.
 class LibraryNamespaces {
  public:
-  LibraryNamespaces() : initialized_(false) {}
+  LibraryNamespaces() : initialized_(false), app_main_namespace_(nullptr) {}
 
   LibraryNamespaces(LibraryNamespaces&&) = default;
   LibraryNamespaces(const LibraryNamespaces&) = delete;
diff --git a/libsparse/output_file.cpp b/libsparse/output_file.cpp
index 5b8179f..c5c4960 100644
--- a/libsparse/output_file.cpp
+++ b/libsparse/output_file.cpp
@@ -17,6 +17,7 @@
 #define _FILE_OFFSET_BITS 64
 #define _LARGEFILE64_SOURCE 1
 
+#include <algorithm>
 #include <fcntl.h>
 #include <inttypes.h>
 #include <limits.h>
@@ -48,13 +49,6 @@
 #define off64_t off_t
 #endif
 
-#define min(a, b)        \
-  ({                     \
-    typeof(a) _a = (a);  \
-    typeof(b) _b = (b);  \
-    (_a < _b) ? _a : _b; \
-  })
-
 #define SPARSE_HEADER_MAJOR_VER 1
 #define SPARSE_HEADER_MINOR_VER 0
 #define SPARSE_HEADER_LEN (sizeof(sparse_header_t))
@@ -231,7 +225,7 @@
   struct output_file_gz* outgz = to_output_file_gz(out);
 
   while (len > 0) {
-    ret = gzwrite(outgz->gz_fd, data, min(len, (unsigned int)INT_MAX));
+    ret = gzwrite(outgz->gz_fd, data, std::min<unsigned int>(len, (unsigned int)INT_MAX));
     if (ret == 0) {
       error("gzwrite %s", gzerror(outgz->gz_fd, nullptr));
       return -1;
@@ -268,7 +262,7 @@
   int ret;
 
   while (off > 0) {
-    to_write = min(off, (int64_t)INT_MAX);
+    to_write = std::min(off, (int64_t)INT_MAX);
     ret = outc->write(outc->priv, nullptr, to_write);
     if (ret < 0) {
       return ret;
@@ -470,7 +464,7 @@
   }
 
   while (len) {
-    write_len = min(len, out->block_size);
+    write_len = std::min(len, out->block_size);
     ret = out->ops->write(out, out->fill_buf, write_len);
     if (ret < 0) {
       return ret;
diff --git a/rootdir/etc/ld.config.txt b/rootdir/etc/ld.config.txt
index 46e9920..a639592 100644
--- a/rootdir/etc/ld.config.txt
+++ b/rootdir/etc/ld.config.txt
@@ -633,15 +633,15 @@
 
 namespace.neuralnetworks.search.paths = /apex/com.android.neuralnetworks/${LIB}
 namespace.neuralnetworks.asan.search.paths = /apex/com.android.neuralnetworks/${LIB}
-namespace.neuralnetworks.links = default
-namespace.neuralnetworks.link.default.shared_libs  = libc.so
-namespace.neuralnetworks.link.default.shared_libs += libcgrouprc.so
-namespace.neuralnetworks.link.default.shared_libs += libdl.so
-namespace.neuralnetworks.link.default.shared_libs += liblog.so
-namespace.neuralnetworks.link.default.shared_libs += libm.so
-namespace.neuralnetworks.link.default.shared_libs += libnativewindow.so
-namespace.neuralnetworks.link.default.shared_libs += libsync.so
-namespace.neuralnetworks.link.default.shared_libs += libvndksupport.so
+namespace.neuralnetworks.links = system
+namespace.neuralnetworks.link.system.shared_libs  = libc.so
+namespace.neuralnetworks.link.system.shared_libs += libcgrouprc.so
+namespace.neuralnetworks.link.system.shared_libs += libdl.so
+namespace.neuralnetworks.link.system.shared_libs += liblog.so
+namespace.neuralnetworks.link.system.shared_libs += libm.so
+namespace.neuralnetworks.link.system.shared_libs += libnativewindow.so
+namespace.neuralnetworks.link.system.shared_libs += libsync.so
+namespace.neuralnetworks.link.system.shared_libs += libvndksupport.so
 
 ###############################################################################
 # Namespace config for native tests that need access to both system and vendor