Merge pull request #278 from rolk/278_linkver

Print linker version to log when configuring

cmake/Modules/OpmLibMain.cmake

@@ -50,6 +50,7 @@ vcs_info ()
 # print toolchain information to identify compilers with potential bugs
 include (UseCompVer)
 compiler_info ()
+linker_info ()
 
 # default settings: build static debug library
 include (OpmDefaults)

cmake/Modules/UseCompVer.cmake

@@ -45,3 +45,34 @@ function (compiler_info)
 	message (STATUS "GNU C++ compiler version: ${version}")
   endif (CMAKE_COMPILER_IS_GNUCXX)
 endfunction (compiler_info)
+
+function (get_ld_version ver_name)
+  # run linker to get the version number. interestingly, this option works
+  # (for our purposes) on all major platforms (Linux, Mac OS X and Windows);
+  # it returns the program version although it may have ended in error
+  exec_program (${CMAKE_LINKER}
+	ARGS "-v"
+	OUTPUT_VARIABLE _version
+	)
+
+  # keep only first line, even on Mac OS X there is no line end
+  list (GET _version 0 _version)
+
+  # format of the version string is platform-specific
+  if (NOT WIN32)
+	if (APPLE)
+	  string (REGEX REPLACE ".*, from Apple (.*\)" "\\1" _version "${_version}")
+	else (APPLE)
+	  # assuming some GNU toolchain now
+	  string (REGEX REPLACE "GNU ([a-zA-Z0-9_]*) (version|\\(.*\\)) ([^\\ ]*).*" "\\1 \\3" _version "${_version}")
+	endif (APPLE)
+  endif (NOT WIN32)
+
+  # return the string to the caller
+  set (${ver_name} "${_version}" PARENT_SCOPE)
+endfunction (get_ld_version ver_name)
+
+function (linker_info)
+  get_ld_version (version)
+  message (STATUS "Linker: ${version}")
+endfunction (linker_info)