Throughout, eliminate argument to sig_dispatch_pending.

* exceptions.cc (setup_handler): Move non-interruptible condition handling
(back) to wait_sig (as suggested by Pierre Humblet).
(set_process_mask): Don't worry about calling sig_dispatch_pending from
sigthread since it is detected in the function anyway.
(sig_handle): Eliminate thisproc arg.  Don't call sig_dispatch_pending on
SIGCONT since that should happen automatically.
* sigproc.cc (sig_dispatch_pending): Eliminate justwake argument.  Just return
when called from sigthread.
(wait_sig): Change some variables to bool.  Change inner while to an if.  Move
uninterruptible signal handling here.
(sigproc_terminate): Don't call sig_dispatch_pending.  Just increment semaphore
on exit.
* speclib: Use slightly different (but still flawed) method for determining
symbols to extract from libraries.

winsup/cygwin/speclib

@@ -18,8 +18,8 @@ nm=$1; shift
 ar=$1; shift
 libdll=$1; shift
 cp /dev/null /tmp/$$.objs
-trap "/bin/rm -rf /tmp/$$.dir /tmp/$$.syms /tmp/$$.objs /tmp/$$.raw" 0 1 2 15
-$nm --extern-only --defined-only $* | sed -e '/^[ 	]*$/d' -e '/:$/d' -e 's%^.* _\(.*\)%/ __imp__\1$/p%' | grep -v ' __imp___imp__' > /tmp/$$.syms
+# trap "/bin/rm -rf /tmp/$$.dir /tmp/$$.syms /tmp/$$.objs /tmp/$$.raw" 0 1 2 15
+$nm --extern-only --defined-only $* | sed -n -e 's%^.* [TD] \(.*\)$%/ \1\$/p%p' > /tmp/$$.syms
 v || $nm -Ap --extern-only --defined-only $libdll | egrep ' I __head| I _.*_iname' |  awk -F: '{print $2}' > /tmp/$$.objs
 $nm -Ap --extern-only --defined-only $libdll | sed -n -f /tmp/$$.syms | awk -F: '{print $2}' >> /tmp/$$.objs
 sort -o /tmp/$$.objs -u /tmp/$$.objs