Merge remote-tracking branch 'origin/2.4' into merge-2.4

Merged pull requests:
	#890 from caorong:patch-1
	#893 from jet47:gpu-arm-fixes
	#933 from pengx17:2.4_macfix_cont
	#935 from pengx17:2.4_filter2d_fix
	#936 from bitwangyaoyao:2.4_perf
	#937 from bitwangyaoyao:2.4_fixPyrLK
	#938 from pengx17:2.4_surf_sample
	#939 from pengx17:2.4_getDevice
	#940 from SpecLad:autolock
	#941 from apavlenko:signed_char
	#946 from bitwangyaoyao:2.4_samples2
	#947 from jet47:fix-gpu-arm-build
	#948 from jet47:cuda-5.5-support
	#952 from SpecLad:jepg
	#953 from jet47:fix-bug-3069
	#955 from SpecLad:symlink
	#957 from pengx17:2.4_fix_corner_detector
	#959 from SpecLad:qt4-build
	#960 from SpecLad:extra-modules

Conflicts:
	modules/core/include/opencv2/core/core.hpp
	modules/gpu/CMakeLists.txt
	modules/gpu/include/opencv2/gpu/device/vec_math.hpp
	modules/gpu/perf/perf_video.cpp
	modules/gpuimgproc/src/cuda/hough.cu
	modules/ocl/include/opencv2/ocl/ocl.hpp
	modules/ocl/src/pyrlk.cpp
	samples/gpu/driver_api_multi.cpp
	samples/gpu/driver_api_stereo_multi.cpp
	samples/ocl/surf_matcher.cpp

cmake/OpenCVCompilerOptions.cmake

@@ -47,6 +47,9 @@ macro(add_extra_compiler_option option)
   endif()
 endmacro()
 
+# OpenCV fails some tests when 'char' is 'unsigned' by default
+add_extra_compiler_option(-fsigned-char)
+
 if(MINGW)
   # http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40838
   # here we are trying to workaround the problem

cmake/OpenCVFindLibsGUI.cmake

@@ -33,7 +33,7 @@ if(WITH_QT)
   endif()
 
   if(NOT HAVE_QT)
-    find_package(Qt4)
+    find_package(Qt4 REQUIRED QtCore QtGui QtTest)
     if(QT4_FOUND)
       set(HAVE_QT TRUE)
       add_definitions(-DHAVE_QT) # We need to define the macro this way, using cvconfig.h does not work

cmake/OpenCVModule.cmake

@@ -303,7 +303,7 @@ macro(ocv_glob_modules)
   # collect modules
   set(OPENCV_INITIAL_PASS ON)
   foreach(__path ${ARGN})
-    ocv_get_real_path(__path "${__path}")
+    get_filename_component(__path "${__path}" ABSOLUTE)
 
     list(FIND __directories_observed "${__path}" __pathIdx)
     if(__pathIdx GREATER -1)
@@ -315,7 +315,7 @@ macro(ocv_glob_modules)
     if(__ocvmodules)
       list(SORT __ocvmodules)
       foreach(mod ${__ocvmodules})
-        ocv_get_real_path(__modpath "${__path}/${mod}")
+        get_filename_component(__modpath "${__path}/${mod}" ABSOLUTE)
         if(EXISTS "${__modpath}/CMakeLists.txt")
 
           list(FIND __directories_observed "${__modpath}" __pathIdx)

cmake/OpenCVUtils.cmake

@@ -411,16 +411,6 @@ macro(ocv_regex_escape var regex)
 endmacro()
 
 
-# get absolute path with symlinks resolved
-macro(ocv_get_real_path VAR PATHSTR)
-  if(CMAKE_VERSION VERSION_LESS 2.8)
-    get_filename_component(${VAR} "${PATHSTR}" ABSOLUTE)
-  else()
-    get_filename_component(${VAR} "${PATHSTR}" REALPATH)
-  endif()
-endmacro()
-
-
 # convert list of paths to full paths
 macro(ocv_convert_to_full_paths VAR)
   if(${VAR})