Revert "Move C headers in extern C context."

This reverts commit e901a56.

This doesn't silence the warnings in clang.

Author: vgvassilev

graf2d/asimage/src/TASImage.cxx

@@ -104,9 +104,9 @@ ROOT tutorials: `$ROOTSYS/tutorials/image/`
 #   include <win32/afterbase.h>
 #   define X_DISPLAY_MISSING 1
 #endif
-extern "C" {
 #   include <afterimage.h>
 #   include <bmp.h>
+extern "C" {
 #   include <draw.h>
 }
 

graf2d/asimage/src/TASPaletteEditor.cxx

@@ -46,8 +46,8 @@ It is called by a pull down menu item of TASImage.
 #   include <win32/config.h>
 #   include <win32/afterbase.h>
 #endif
-extern "C" {
 #   include <afterimage.h>
+extern "C" {
 #   include <bmp.h>
 }
 

tmva/pymva/src/MethodPyAdaBoost.cxx

@@ -17,9 +17,7 @@
  *                                                                                *
  **********************************************************************************/
 
-extern "C" {
-   #include <Python.h> // Needs to be included first to avoid redefinition of _POSIX_C_SOURCE
-}
+#include <Python.h> // Needs to be included first to avoid redefinition of _POSIX_C_SOURCE
 #include "TMVA/MethodPyAdaBoost.h"
 
 #define NPY_NO_DEPRECATED_API NPY_1_7_API_VERSION

tmva/pymva/src/MethodPyGTB.cxx

@@ -17,9 +17,7 @@
  *                                                                                *
  **********************************************************************************/
 
-extern "C" {
-   #include <Python.h>    // Needs to be included first to avoid redefinition of _POSIX_C_SOURCE
-}
+#include <Python.h>    // Needs to be included first to avoid redefinition of _POSIX_C_SOURCE
 #include "TMVA/MethodPyGTB.h"
 
 #define NPY_NO_DEPRECATED_API NPY_1_7_API_VERSION

tmva/pymva/src/MethodPyKeras.cxx

@@ -1,9 +1,7 @@
 // @(#)root/tmva/pymva $Id$
 // Author: Stefan Wunsch, 2016
 
-extern "C" {
-   #include <Python.h>
-}
+#include <Python.h>
 #include "TMVA/MethodPyKeras.h"
 
 #define NPY_NO_DEPRECATED_API NPY_1_7_API_VERSION

tmva/pymva/src/MethodPyRandomForest.cxx

@@ -16,9 +16,7 @@
  * (http://tmva.sourceforge.net/LICENSE)                                          *
  *                                                                                *
  **********************************************************************************/
-extern "C" {
-   #include <Python.h>    // Needs to be included first to avoid redefinition of _POSIX_C_SOURCE
-}
+#include <Python.h>    // Needs to be included first to avoid redefinition of _POSIX_C_SOURCE
 #include "TMVA/MethodPyRandomForest.h"
 
 #define NPY_NO_DEPRECATED_API NPY_1_7_API_VERSION

tmva/pymva/src/PyMethodBase.cxx

@@ -11,9 +11,7 @@
  *                                                                                *
  **********************************************************************************/
 
-extern "C" {
-   #include <Python.h> // Needs to be included first to avoid redefinition of _POSIX_C_SOURCE
-}
+#include <Python.h> // Needs to be included first to avoid redefinition of _POSIX_C_SOURCE
 #include <TMVA/PyMethodBase.h>
 
 #include "TMVA/DataSet.h"