opencv fails to build in a directory with ++

[starius]

Similar to #1087 and #1030

From log:

-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detected version of GNU GCC: 49 (409)
RegularExpression::compile(): Nested *?+.
RegularExpression::compile(): Error in compile.
CMake Error at cmake/OpenCVUtils.cmake:42 (if):
  if given arguments:

    "/home/mxe/mxe-libmysqlclient-++-plus-plus/tmp-opencv-i686-w64-mingw32.static/opencv-2.4.10.build" "MATCHES" "^/home/mxe/mxe-libmysqlclient-++-plus-plus/tmp-opencv-i686-w64-mingw32.static/opencv-2.4.10" "OR" "/home/mxe/mxe-libmysqlclient-++-plus-plus/tmp-opencv-i686-w64-mingw32.static/opencv-2.4.10.build" "MATCHES" "^/home/mxe/mxe-libmysqlclient-++-plus-plus/tmp-opencv-i686-w64-mingw32.static/opencv-2.4.10.build"

  Regular expression
  "^/home/mxe/mxe-libmysqlclient-++-plus-plus/tmp-opencv-i686-w64-mingw32.static/opencv-2.4.10"
  cannot compile
Call Stack (most recent call first):
  CMakeLists.txt:348 (ocv_include_directories)


-- Configuring incomplete, errors occurred!

[tonytheodore]

At this point, we need to deal with it at the cmake level.

[starius]

The code is as follows:

# cmake/OpenCVUtils.cmake:42
if("${__abs_dir}" MATCHES "^${OpenCV_SOURCE_DIR}" OR
   "${__abs_dir}" MATCHES "^${OpenCV_BINARY_DIR}")

It checks if ${__abs_dir} is a subdirectory starts with ${OpenCV_SOURCE_DIR} or ${OpenCV_BINARY_DIR}. It can be replaced with getting a prefix and comparing with STREQUAL.

[starius]

Or use FIND:

string(FIND "${__abs_dir}" "${OpenCV_SOURCE_DIR}" OpenCV_SOURCE_DIR_offset)
string(FIND "${__abs_dir}" "${OpenCV_BINARY_DIR}" OpenCV_BINARY_DIR_offset)
if($OpenCV_BINARY_DIR_offset} EQUAL 0 OR ${OpenCV_BINARY_DIR_offset} EQUAL 0)