libc: Update auto-gen scripts

Make the scripts use external/kernel-headers/original by default.

clean_header.py:  Document -k<path>, add -d<path>
find_headers.py:  Make kernel config files optional
update_all.py:    Allow setting the path to kernel headers on the command-line
update_all.py:    Better formatting of output on ttys
update_all.py:    Automatically perform "git add/rm" on affected files.
SYSCALLS.TXT:     Fix typo in __socketcall definition.
checksyscalls.py: Add support for superH architecture in the checks.
gensyscalls.py:   Automatically perform "git add/rm" on affected files.
cpp.py:           Fixed a bug that prevented certain type definitions to
                  be kept in the generated clean header (e.g.
                  struct ethtool_drvinfo in <linux/ethtool.h>)

All scripts will use the content of external/kernel-headers/original by default now.

The generated code removes all empty lines and trailing whitespace. This is useful
to ensure a unified output even if we change the parser again in the future.

The top-level disclaimer has been edited with update instructions to regenerate
the headers when needed.

Also, a warning is now inserted every 8th line in the final output:

/* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */

Changes under kernel/arch-arm and kernel/arch-x86 should correspond to whitespace
differences and additionnal struct definitions that were missed by the previous
parser implementation.

Change-Id: Icd1c056bacd766759f3e9b7bb5d63a246f3d656a

WARNING: If you run these script, do not submit the result to gerrit for now.
         It seems there are discrepancies between the content of original headers
         and those currently commited under bionic/libc/kernel/.

         (This problem is the main motivation to insert the warning repeatedly).

         Current list of issues:

           - Missing SuperH headers (i.e. external/kernel-headers/original/asm-sh)

libc/kernel/tools/utils.py

@@ -231,6 +231,15 @@ def create_file_path(path):
 def walk_source_files(paths,callback,args,excludes=[]):
     """recursively walk a list of paths and files, only keeping the source files in directories"""
     for path in paths:
+        if len(path) > 0 and path[0] == '@':
+            # this is the name of another file, include it and parse it
+            path = path[1:]
+            if os.path.exists(path):
+                for line in open(path):
+                    if len(line) > 0 and line[-1] == '\n':
+                        line = line[:-1]
+                    walk_source_files([line],callback,args,excludes)
+            continue
         if not os.path.isdir(path):
             callback(path,args)
         else:
@@ -238,7 +247,7 @@ def walk_source_files(paths,callback,args,excludes=[]):
                 #print "w-- %s (ex: %s)" % (repr((root,dirs)), repr(excludes))
                 if len(excludes):
                     for d in dirs[:]:
-                        if d in excludes:
+                        if os.path.join(root,d) in excludes:
                             dirs.remove(d)
                 for f in files:
                     r, ext = os.path.splitext(f)
@@ -395,3 +404,19 @@ class BatchFileUpdater:
             D2("P4 DELETES: %s" % files)
             o = commands.getoutput( "p4 delete " + files )
             D2( o )
+
+    def updateGitFiles(self):
+        adds, deletes, edits = self.getChanges()
+
+        if adds:
+            for dst in sorted(adds):
+                self._writeFile(dst)
+            commands.getoutput("git add " + " ".join(adds))
+
+        if deletes:
+            commands.getoutput("git rm " + " ".join(deletes))
+
+        if edits:
+            for dst in sorted(edits):
+                self._writeFile(dst)
+            commands.getoutput("git add " + " ".join(edits))