That's from src/support/os_win32.C in the init() function. Here "sh -c uname" is tried in order to detect a cygwin environment. If the command is not found, it is assumed that there is no such environment. Hence, the warning is not harmful.
If you only want to check if an environment is cygwin, can you check the existance of /cygdrive? something like boost::fileexists(...). At least, this command can be replaced to 'python -c 'import sys;print sys.platform'. Bo
