fix asyncs running in the vm; re-enable popen.scm compilation

* libguile/vm-i-system.c (goto/args): Sync the registers before doing the
  SCM_TICK. We probably need a different SCM_TICK that saves the regs
  only if necessary. This fixes GC problems with a compiled popen.scm.

* ice-9/Makefile.am: Re-enable popen.scm compilation.

ice-9/Makefile.am

@@ -36,7 +36,7 @@ SOURCES = psyntax-pp.scm boot-9.scm \
 	format.scm getopt-long.scm hcons.scm i18n.scm			\
 	lineio.scm ls.scm mapping.scm					\
 	networking.scm null.scm optargs.scm poe.scm		\
-	posix.scm q.scm r4rs.scm r5rs.scm			\
+	popen.scm posix.scm q.scm r4rs.scm r5rs.scm			\
 	rdelim.scm receive.scm regex.scm runq.scm rw.scm		\
 	safe-r5rs.scm safe.scm session.scm slib.scm stack-catch.scm	\
 	streams.scm string-fun.scm syncase.scm threads.scm		\
@@ -49,16 +49,13 @@ SOURCES = psyntax-pp.scm boot-9.scm \
 # snarf-check-and-output-texi) fails. need to figure out what the
 # problem is.
 #
-# popen.scm compiles, but then breaks the test suite via random lost gc
-# references. need to figure out what's going on there.
-# 
 # occam-channel and gds-client use goops, which is not yet vm-compatible
 # (it does some compilation-like optimizations for the interpreter), so
 # punt on them for the time being.
 #
 # psyntax.scm needs help. fortunately it's only needed when recompiling
 # psyntax-pp.scm.
-NOCOMP_SOURCES = match.scm occam-channel.scm gds-client.scm psyntax.scm popen.scm
+NOCOMP_SOURCES = match.scm occam-channel.scm gds-client.scm psyntax.scm
 
 include $(top_srcdir)/guilec.mk
 

libguile/vm-i-system.c

@@ -604,6 +604,7 @@ VM_DEFINE_INSTRUCTION (goto_args, "goto/args", 1, -1, 1)
  vm_goto_args:
   x = sp[-nargs];
 
+  SYNC_REGISTER ();
   SCM_TICK;	/* allow interrupt here */
 
   /*