Remove C compiler requirement from FindQt4.cmake

Use the new check_cxx_symbol_exists instead of check_symbol_exists.
Also remove a debug message from CheckSymbolExists.cmake.

Modules/CheckSymbolExists.cmake

@@ -40,7 +40,6 @@ MACRO(CHECK_SYMBOL_EXISTS SYMBOL FILES VARIABLE)
 ENDMACRO(CHECK_SYMBOL_EXISTS)
 
 MACRO(_CHECK_SYMBOL_EXISTS SOURCEFILE SYMBOL FILES VARIABLE)
-message(STATUS "files: -${FILES}-")
   IF("${VARIABLE}" MATCHES "^${VARIABLE}$")
     SET(CMAKE_CONFIGURABLE_FILE_CONTENT "/* */\n")
     SET(MACRO_CHECK_SYMBOL_EXISTS_FLAGS ${CMAKE_REQUIRED_FLAGS})

Modules/FindQt4.cmake

@@ -352,7 +352,7 @@ IF(QT_QT_LIBRARY)
 ENDIF(QT_QT_LIBRARY)
 
 
-INCLUDE(CheckSymbolExists)
+INCLUDE(CheckCXXSymbolExists)
 INCLUDE(MacroAddFileDependencies)
 INCLUDE(${CMAKE_CURRENT_LIST_DIR}/FindPackageHandleStandardArgs.cmake)
 
@@ -715,19 +715,19 @@ IF (QT_QMAKE_EXECUTABLE AND QTVERSION)
   # Add QT_INCLUDE_DIR to CMAKE_REQUIRED_INCLUDES
   SET(CMAKE_REQUIRED_INCLUDES "${CMAKE_REQUIRED_INCLUDES};${QT_INCLUDE_DIR}")
   # Check for Window system symbols (note: only one should end up being set)
-  CHECK_SYMBOL_EXISTS(Q_WS_X11 "QtCore/qglobal.h" Q_WS_X11)
-  CHECK_SYMBOL_EXISTS(Q_WS_WIN "QtCore/qglobal.h" Q_WS_WIN)
-  CHECK_SYMBOL_EXISTS(Q_WS_QWS "QtCore/qglobal.h" Q_WS_QWS)
-  CHECK_SYMBOL_EXISTS(Q_WS_MAC "QtCore/qglobal.h" Q_WS_MAC)
+  CHECK_CXX_SYMBOL_EXISTS(Q_WS_X11 "QtCore/qglobal.h" Q_WS_X11)
+  CHECK_CXX_SYMBOL_EXISTS(Q_WS_WIN "QtCore/qglobal.h" Q_WS_WIN)
+  CHECK_CXX_SYMBOL_EXISTS(Q_WS_QWS "QtCore/qglobal.h" Q_WS_QWS)
+  CHECK_CXX_SYMBOL_EXISTS(Q_WS_MAC "QtCore/qglobal.h" Q_WS_MAC)
   IF(Q_WS_MAC)
     IF(QT_QMAKE_CHANGED)
       UNSET(QT_MAC_USE_COCOA CACHE)
     ENDIF(QT_QMAKE_CHANGED)
-    CHECK_SYMBOL_EXISTS(QT_MAC_USE_COCOA "QtCore/qconfig.h" QT_MAC_USE_COCOA)
+    CHECK_CXX_SYMBOL_EXISTS(QT_MAC_USE_COCOA "QtCore/qconfig.h" QT_MAC_USE_COCOA)
   ENDIF(Q_WS_MAC)
 
   IF (QT_QTCOPY_REQUIRED)
-     CHECK_SYMBOL_EXISTS(QT_IS_QTCOPY "QtCore/qglobal.h" QT_KDE_QT_COPY)
+     CHECK_CXX_SYMBOL_EXISTS(QT_IS_QTCOPY "QtCore/qglobal.h" QT_KDE_QT_COPY)
      IF (NOT QT_IS_QTCOPY)
         MESSAGE(FATAL_ERROR "qt-copy is required, but hasn't been found")
      ENDIF (NOT QT_IS_QTCOPY)