flux-module: display dlerror() on failure

We had a silent exit(1) on flux module load by path where
the file exists but dlopen()/dlsym() fails.  dlopen() fails
when there is any unresolved symbol, so expect this to happen.
build: fix typo in pkg-config file

Typo was preventing flux-core.pc from working properly when installed
to a prefix in home directory.
build: include flux_barrier() in -lflux-core
Merge pull request #10 from grondo/keygen-fixes-3

keygen fixes
Merge pull request #9 from garlick/misc-fixes

Misc fixes
keygen: Fix curve key generation

zmq_curve_keypair() generates keys with z85 encoding, but
zcert_new_from() expected decoded keys. Therefore, decode keys
with zmq_z85_decode() first before passing to zcert_new_from().

Yes, this seems like unnecessary work, but we use zmq_curve_keypair()
to ensure that zeroed keys are not silently generated in zcert_new(),
and this operation should only occur rarely, during 'flux keygen' so
we are not too worried about speed.
remove references to --curve in flux-keygen

flux-keygen didn't actually export -c, --curve option, and curve
is the default anyway, so remove all references to the 'curve' option
in the code to avoid confusion.
security: fix crash in genpasswd

genpasswd() tried to free 'passwd' as returned from zuuid_str(), but
the return value from zuuid_str() is not allocated with malloc but
is part of the zuuid_t object itself (and thus will be freed with
zuuid_destroy()).

This fixes a crash in flux-keygen --plain.
Merge pull request #12 from grondo/zcert_curve_new-fix

More keygen fixes
autoconf: Fix quoting in X_AC_CHECK_COND_LIB

Add missing quote around AC_LANG_PROGRAM invocation.

https://lists.gnu.org/archive/html/bug-autoconf/2011-04/msg00015.html

Fixes #3
autoconf: Fix quoting in X_AC_ZEROMQ

Add source in AC_LANG_SOURCE.
AC_LANG_SOURCE needs to be double-quoted so we don't blow
away matching brackets in C source. (e.g. char x[41]; -> char x41;)