Problem: AC_CHECK_FILE fails when cross-compiling
Problem: AC_CHECK_FILE fails when cross-compiling

Solution: don't do it and default the check for CMakeLists.txt to
false when cross-compiling. It is extremely unlikely that a
distributable tarball which includes the CMake files would have
to be created with cross-compilation anyway.

zeromq/zproject,paddor/zproject,taotetek/zproject,paddor/zproject,zeromq/zproject,zeromq/zproject,taotetek/zproject,taotetek/zproject,paddor/zproject