Revert "Revert "Add a way to turn off unique_fd's operator int.""

The original commit broke aosp-master-with-phones, because of
vendor libraries the depended on the int versions of libbase functions.

This patch reverts the revert, and also adds ABI-compatibility shims for
the replaced functions.

This reverts commit 2c58e1924a7bf1b44049764fddb40c1704dc288f.

Bug: http://b/131312539
Test: treehugger
Test: forrest run of aosp-master-with-phones
Change-Id: I75cc84ec8d963e20862f7662e8e2f409471f41cc
diff --git a/adb/adb_utils.cpp b/adb/adb_utils.cpp
index 9791769..cf5fbc8 100644
--- a/adb/adb_utils.cpp
+++ b/adb/adb_utils.cpp
@@ -234,15 +234,15 @@
 
 #if !defined(_WIN32)
 // Windows version provided in sysdeps_win32.cpp
-bool set_file_block_mode(int fd, bool block) {
-    int flags = fcntl(fd, F_GETFL, 0);
+bool set_file_block_mode(borrowed_fd fd, bool block) {
+    int flags = fcntl(fd.get(), F_GETFL, 0);
     if (flags == -1) {
-        PLOG(ERROR) << "failed to fcntl(F_GETFL) for fd " << fd;
+        PLOG(ERROR) << "failed to fcntl(F_GETFL) for fd " << fd.get();
         return false;
     }
     flags = block ? (flags & ~O_NONBLOCK) : (flags | O_NONBLOCK);
-    if (fcntl(fd, F_SETFL, flags) != 0) {
-        PLOG(ERROR) << "failed to fcntl(F_SETFL) for fd " << fd << ", flags " << flags;
+    if (fcntl(fd.get(), F_SETFL, flags) != 0) {
+        PLOG(ERROR) << "failed to fcntl(F_SETFL) for fd " << fd.get() << ", flags " << flags;
         return false;
     }
     return true;