This is likely to be the case when building from a tar ball release
package which includes a prebuilt man page. In that case, test the
packaged man page instead. This only makes a difference when building
out-of-tree (in-tree, the location in both cases is identical).
This script now also scans src/tool_getparam.c, docs/curl.1 and
src/tool_help.c and will warn if any of them lists a command line option
not mentioned in one of the other places.
