Re: [PATCH] configure: use AC_SEARCH_LIBS instead of AC_CHECK_LIB

After actually reading the autoconf documentation, don't some of the tests have the [action-if-found] and [action-if-not-found] actions backwards?

AC_CHECK_LIB has the form:

   AC_CHECK_LIB (library, function, [action-if-found], [action-if-not-found], [other-libraries])

The test I added (which I blindly copied from the NEEDS_RESOLV test) looks like:

   AC_CHECK_LIB([gen], [basename], [NEEDS_LIBGEN=], [NEEDS_LIBGEN=YesPlease])
   AC_SUBST(NEEDS_LIBGEN)
   test -n "$NEEDS_LIBGEN" && LIBS="$LIBS -lgen"

Won't this check whether a program which calls basename() successfully links with -lgen? If it successfully links, then it will perform NEED_LIBGEN= and if not it will set NEEDS_LIBGEN=YesPlease, right? Isn't that the opposite of what should be done?

If that is correct, then the NEEDS_RESOLV and NEEDS_LIBGEN tests are wrong and they may still be wrong even if AC_SEARCH_LIBS is used instead of AC_CHECK_LIB.

A question about AC_SEARCH_LIBS:

With AC_SEARCH_LIBS, which of [action-if-found] or [action-if-not-found] is executed if the function is found in the standard c library i.e. "calling `AC_LINK_IFELSE([AC_LANG_CALL([], [function])])' first with no libraries"? Is the answer neither? If the answer is [action-if-found], won't the NEEDS_LIBGEN=YesPlease be set when the function is found in the c library? Assuming the NEEDS_LIBGEN test is made to look like this:

   AC_SEARCH_LIBS([basename], [gen], [NEEDS_LIBGEN=YesPlease], [NEEDS_LIBGEN=])

Depending on the answer to that question, we either will want to use AC_SEARCH_LIBS, or stick with AC_CHECK_LIB but correct the [action] fields, or maybe even stick with AC_CHECK_LIB but rework the NEEDS_RESOLV and NEEDS_LIBGEN tests to look like the NEEDS_SOCKET test.

-brandon