Fetching anything segfaults when Pextlib calls system Tcl

[Greg Earle]

I'm on a Mac Pro running 10.6.8.  Did a selfupdate (to 2.1.2)
and now anything I try to do that involves a fetch is croaking
with a Segmentation fault:

[4:06] nightowl:~ % sudo port -v 
MacPorts 2.1.2
Entering interactive mode... ("help" for help, "quit" to quit)
[Users/earle] > upgrade outdated
--->  Computing dependencies for automake.
--->  Fetching archive for automake
--->  automake-1.12.4_0.darwin_10.noarch.tbz2 doesn't seem to exist in /opt/local/var/macports/incoming/verified
--->  Attempting to fetch automake-1.12.4_0.darwin_10.noarch.tbz2 from http://packages.macports.org/automake
Segmentation fault

I tried to trace it via "sudo dtruss port -v upgrade outdated" and it
caused a kernel panic and crashed the system!  Oops.

It looks like MacPorts' Pextlib library (MacPorts 2.1.2 libcurl/7.10.4)
is calling the system tclsh8.5 (Tcl Shell 8.5.7) and it's croaking on
a strlen() call:

--
Process:         tclsh8.5 [88796]
Path:            /System/Library/Frameworks/Tcl.framework/Versions/8.5/tclsh8.5
Identifier:      tclsh8.5
Version:         ??? (???)
Code Type:       X86-64 (Native)
Parent Process:  tcsh [21863]

PlugIn Path:       /opt/local/share/macports/Tcl/pextlib1.0/Pextlib.dylib
PlugIn Identifier: Pextlib.dylib
PlugIn Version:    ??? (???)

Date/Time:       2012-11-16 04:09:51.318 -0800
OS Version:      Mac OS X 10.6.8 (10K549)
Report Version:  6

Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0xffffffff87023170
Crashed Thread:  0  Dispatch queue: com.apple.main-thread

Thread 0 Crashed:  Dispatch queue: com.apple.main-thread
0   libSystem.B.dylib             	0x00007fff85270c00 strlen + 16
1   Tcl                           	0x000000010008a350 Tcl_SetResult + 83
2   Pextlib.dylib                 	0x000000010070e617 SetResultFromCurlErrorCode + 103
3   Pextlib.dylib                 	0x000000010070f47c CurlFetchCmd + 1420
4   Pextlib.dylib                 	0x000000010070f788 CurlCmd + 184
[...]
--

It looks quite a bit like Ticket 31472

https://trac.macports.org/ticket/31472

with a slightly different stack traceback.  (I have no network problems.)

Am I hosed?

	- Greg