Added test for grep.

CMakeLists.txt

@@ -8,9 +8,13 @@ set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR})
 execute_process(
 	COMMAND grep "NABO_VERSION " nabo/nabo.h
 	WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+	RESULT_VARIABLE GREP_VERSION_RESULT
 	OUTPUT_VARIABLE PROJECT_VERSION
 	OUTPUT_STRIP_TRAILING_WHITESPACE
 )
+if (NOT GREP_VERSION_RESULT EQUAL 0)
+	message(SEND_ERROR "Cannot grep version number: ${GREP_VERSION_RESULT}")
+endif (NOT GREP_VERSION_RESULT EQUAL 0)
 string(REGEX REPLACE ".*\"(.*)\".*" "\\1" PROJECT_VERSION "${PROJECT_VERSION}" )
 
 # Documentation

README.md

@@ -36,6 +36,7 @@ Prerequisites
 
 If your operating system does not provide it, you must get [Eigen] and [Boost].
 [Eigen] only needs to be downloaded and extracted.
+You also need `grep`, which is available in standard on Linux or Mac OS X, you can get the window version [here](http://gnuwin32.sourceforge.net/packages/grep.htm).
 
 Compilation options
 -------------------