4 files changed, 1 insertions, 31 deletions
diff --git a/src/corelib/global/qcompilerdetection.h b/src/corelib/global/qcompilerdetection.h
index db5f6f3bb1..77f6c48857 100644
--- a/src/corelib/global/qcompilerdetection.h
+++ b/src/corelib/global/qcompilerdetection.h
@@ -136,7 +136,6 @@
 
 #elif defined(__GNUC__)
 #  define Q_CC_GNU          (__GNUC__ * 100 + __GNUC_MINOR__)
-#  define Q_C_CALLBACKS
 #  if defined(__MINGW32__)
 #    define Q_CC_MINGW
 #  endif
@@ -312,7 +311,6 @@
 /* The Comeau compiler is based on EDG and does define __EDG__ */
 #  if defined(__COMO__)
 #    define Q_CC_COMEAU
-#    define Q_C_CALLBACKS
 
 /* The `using' keyword was introduced to avoid KAI C++ warnings
    but it's now causing KAI C++ errors instead. The standard is
@@ -396,7 +394,6 @@
 #    if !defined(_BOOL)
 #      error "Compiler not supported"
 #    endif
-#    define Q_C_CALLBACKS
 /* 4.2 compiler or older */
 #  else
 #    error "Compiler not supported"
diff --git a/src/corelib/thread/qthread_unix.cpp b/src/corelib/thread/qthread_unix.cpp
index 9a14503584..09659297d0 100644
--- a/src/corelib/thread/qthread_unix.cpp
+++ b/src/corelib/thread/qthread_unix.cpp
@@ -241,15 +241,9 @@ void QAdoptedThread::init()
    QThreadPrivate
 */
 
-#if defined(Q_C_CALLBACKS)
 extern "C" {
-#endif
-
 typedef void*(*QtThreadCallback)(void*);
-
-#if defined(Q_C_CALLBACKS)
 }
-#endif
 
 #endif // QT_NO_THREAD
 
diff --git a/src/gui/image/qjpeghandler.cpp b/src/gui/image/qjpeghandler.cpp
index 7b669b1181..eb580c81f1 100644
--- a/src/gui/image/qjpeghandler.cpp
+++ b/src/gui/image/qjpeghandler.cpp
@@ -86,9 +86,7 @@ struct my_error_mgr : public jpeg_error_mgr {
     jmp_buf setjmp_buffer;
 };
 
-#if defined(Q_C_CALLBACKS)
 extern "C" {
-#endif
 
 static void my_error_exit (j_common_ptr cinfo)
 {
@@ -106,9 +104,7 @@ static void my_output_message(j_common_ptr cinfo)
     qWarning("%s", buffer);
 }
 
-#if defined(Q_C_CALLBACKS)
 }
-#endif
 
 
 static const int max_buf = 4096;
@@ -123,9 +119,7 @@ public:
     my_jpeg_source_mgr(QIODevice *device);
 };
 
-#if defined(Q_C_CALLBACKS)
 extern "C" {
-#endif
 
 static void qt_init_source(j_decompress_ptr)
 {
@@ -185,9 +179,7 @@ static void qt_term_source(j_decompress_ptr cinfo)
         src->device->seek(src->device->pos() - src->bytes_in_buffer);
 }
 
-#if defined(Q_C_CALLBACKS)
 }
-#endif
 
 inline my_jpeg_source_mgr::my_jpeg_source_mgr(QIODevice *device)
 {
@@ -458,9 +450,7 @@ public:
 };
 
 
-#if defined(Q_C_CALLBACKS)
 extern "C" {
-#endif
 
 static void qt_init_destination(j_compress_ptr)
 {
@@ -490,9 +480,7 @@ static void qt_term_destination(j_compress_ptr cinfo)
         (*cinfo->err->error_exit)((j_common_ptr)cinfo);
 }
 
-#if defined(Q_C_CALLBACKS)
 }
-#endif
 
 inline my_jpeg_destination_mgr::my_jpeg_destination_mgr(QIODevice *device)
 {
diff --git a/src/gui/image/qpnghandler.cpp b/src/gui/image/qpnghandler.cpp
index d09ed0fda7..c19bc52a97 100644
--- a/src/gui/image/qpnghandler.cpp
+++ b/src/gui/image/qpnghandler.cpp
@@ -157,10 +157,6 @@ public:
 };
 
 
-#if defined(Q_C_CALLBACKS)
-extern "C" {
-#endif
-
 class QPNGImageWriter {
 public:
     explicit QPNGImageWriter(QIODevice*);
@@ -190,6 +186,7 @@ private:
     float gamma;
 };
 
+extern "C" {
 static
 void CALLBACK_CALL_TYPE iod_read_fn(png_structp png_ptr, png_bytep data, png_size_t length)
 {
@@ -234,9 +231,7 @@ void CALLBACK_CALL_TYPE qpiw_flush_fn(png_structp /* png_ptr */)
 {
 }
 
-#if defined(Q_C_CALLBACKS)
 }
-#endif
 
 static
 void setup_qt(QImage& image, png_structp png_ptr, png_infop info_ptr, QSize scaledSize, bool *doScaledRead, float screen_gamma=0.0)
@@ -492,17 +487,13 @@ static void read_image_scaled(QImage *outImage, png_structp png_ptr, png_infop i
 
 }
 
-#if defined(Q_C_CALLBACKS)
 extern "C" {
-#endif
 static void CALLBACK_CALL_TYPE qt_png_warning(png_structp /*png_ptr*/, png_const_charp message)
 {
     qWarning("libpng warning: %s", message);
 }
 
-#if defined(Q_C_CALLBACKS)
 }
-#endif
 
 
 void Q_INTERNAL_WIN_NO_THROW QPngHandlerPrivate::readPngTexts(png_info *info)