Merge changes from team/russell/http_filetxfer

Handle transferring large files from the built-in http server.  Previously, the
code attempted to malloc a block as large as the file itself.  Now it uses the
sendfile() system call so that the file isn't copied into userspace at all if
it is available.  Otherwise, it just uses a read/write of small chunks at a time.


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@72701 65c4cc65-6c06-0410-ace0-fbb531ad65f3

configure

@@ -1,5 +1,5 @@
 #! /bin/sh
-# From configure.ac Revision: 71732 .
+# From configure.ac Revision: 72539 .
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.61.
 #
@@ -16476,6 +16476,66 @@ _ACEOF
 
 
 
+cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+#include <stdlib.h>
+     #include <sys/sendfile.h>
+int
+main ()
+{
+sendfile(1, 0, NULL, 1);
+  ;
+  return 0;
+}
+
+_ACEOF
+rm -f conftest.$ac_objext
+if { (ac_try="$ac_compile"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_compile") 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && {
+	 test -z "$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       } && test -s conftest.$ac_objext; then
+
+    { echo "$as_me:$LINENO: result: yes" >&5
+echo "${ECHO_T}yes" >&6; }
+       have_sendfile=yes
+
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+
+    { echo "$as_me:$LINENO: result: no" >&5
+echo "${ECHO_T}no" >&6; }
+       have_sendfile=no
+
+
+fi
+
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+if test "${have_sendfile}" = "yes"; then
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_SENDFILE 1
+_ACEOF
+
+fi
+
 # do the package library checks now