Steps to fix io head only

out.txt

-> % gcc --version
i686-apple-darwin11-llvm-gcc-4.2 (GCC) 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.15.00)
Copyright (C) 2007 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

developer@mbp13 [03:02:37] [/usr/local/Library/Formula] [local_master]
-> % brew install io
==> Cloning https://github.com/stevedekorte/io.git
Updating /Users/developer/Library/Caches/Homebrew/io--git
==> Downloading patches
==> Patching
patching file addons/Image/CMakeLists.txt
==> cmake .. -DCMAKE_INSTALL_PREFIX='/usr/local/Cellar/io/HEAD' -DCMAKE_BUILD_TYPE=None -Wno-dev
==> make install
Scanning dependencies of target copy_basekit_headers
[  0%] Copying files: /tmp/homebrew-io-HEAD-um2f//tmp/homebrew-io-HEAD-um2f/libs/basekit/source/*.h to /tmp/homebrew-io-HEAD-um2f/io-build/_build/headers
[  1%] Built target copy_basekit_headers
Scanning dependencies of target copy_coroutine_headers
[  1%] Copying files: /tmp/homebrew-io-HEAD-um2f//tmp/homebrew-io-HEAD-um2f/libs/coroutine/source/*.h to /tmp/homebrew-io-HEAD-um2f/io-build/_build/headers
[  1%] Built target copy_coroutine_headers
Scanning dependencies of target copy_garbagecollector_headers
[  1%] Copying files: /tmp/homebrew-io-HEAD-um2f//tmp/homebrew-io-HEAD-um2f/libs/garbagecollector/source/*.h to /tmp/homebrew-io-HEAD-um2f/io-build/_build/headers
[  1%] Built target copy_garbagecollector_headers
Scanning dependencies of target copy_iovm_headers
[  1%] Copying files: /tmp/homebrew-io-HEAD-um2f//tmp/homebrew-io-HEAD-um2f/libs/iovm/source/*.h to /tmp/homebrew-io-HEAD-um2f/io-build/_build/headers
[  1%] Built target copy_iovm_headers
Scanning dependencies of target io2c
[  1%] Building C object libs/iovm/tools/CMakeFiles/io2c.dir/io2c.c.o
Linking C executable ../../../_build/binaries/io2c
[  1%] Built target io2c
Scanning dependencies of target coroutine
[  2%] Building C object libs/coroutine/CMakeFiles/coroutine.dir/source/context.c.o
[  2%] Building C object libs/coroutine/CMakeFiles/coroutine.dir/source/Coro.c.o
[  2%] Building C object libs/coroutine/CMakeFiles/coroutine.dir/source/asm.S.o
Linking C shared library ../../_build/dll/libcoroutine.dylib
[  2%] Built target coroutine
Scanning dependencies of target basekit
[  2%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/BStream.c.o
[  3%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/BStreamTag.c.o
[  3%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/cdecode.c.o
[  3%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/cencode.c.o
[  4%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/CHash.c.o
[  4%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/Common.c.o
[  4%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/Date.c.o
[  4%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/Duration.c.o
[  5%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/DynLib.c.o
[  5%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/Hash_fnv.c.o
[  5%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/Hash_murmur.c.o
[  5%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/Hash_superfast.c.o
[  6%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/List.c.o
[  6%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/MainArgs.c.o
[  6%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/PointerHash.c.o
[  7%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/PortableGettimeofday.c.o
[  7%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/PortableSnprintf.c.o
[  7%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/PortableSorting.c.o
[  7%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/PortableStrlcpy.c.o
[  8%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/PortableStrptime.c.o
[  8%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/PortableTruncate.c.o
[  8%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/PortableUsleep.c.o
[  9%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/RandomGen.c.o
[  9%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/Stack.c.o
[  9%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/UArray.c.o
[  9%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/UArray_character.c.o
[ 10%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/UArray_format.c.o
[ 10%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/UArray_math.c.o
[ 10%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/UArray_path.c.o
[ 11%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/UArray_stream.c.o
[ 11%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/UArray_string.c.o
[ 11%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/UArray_utf.c.o
[ 11%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/ucs2.c.o
[ 12%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/ucs4.c.o
[ 12%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/utf8.c.o
[ 12%] Building C object libs/basekit/CMakeFiles/basekit.dir/source/utf_convert.c.o
Linking C shared library ../../_build/dll/libbasekit.dylib
ld: duplicate symbol _List_size in CMakeFiles/basekit.dir/source/Stack.c.o and CMakeFiles/basekit.dir/source/List.c.o for architecture x86_64
collect2: ld returned 1 exit status
make[2]: *** [_build/dll/libbasekit.dylib] Error 1
make[1]: *** [libs/basekit/CMakeFiles/basekit.dir/all] Error 2
make: *** [all] Error 2
==> Exit Status: 2
http://github.com/mxcl/homebrew/blob/master/Library/Formula/io.rb#L24
==> Environment
HOMEBREW_VERSION: 0.8
HEAD: 8092800989d7c74638679ac6f4d6eba3f844f98e
HOMEBREW_PREFIX: /usr/local
HOMEBREW_CELLAR: /usr/local/Cellar
HOMEBREW_REPOSITORY: /usr/local
HOMEBREW_LIBRARY_PATH: /usr/local/Library/Homebrew
Hardware: dual-core 64-bit penryn
OS X: 10.7
Kernel Architecture: x86_64
Ruby: 1.8.7-249
/usr/bin/ruby => /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby
Xcode: 4.1
GCC-4.0: N/A 
GCC-4.2: build 5666 
LLVM: build 2335 
MacPorts or Fink? false
X11 installed? true
==> Build Flags
CC: /usr/bin/cc => /usr/llvm-gcc-4.2/bin/llvm-gcc-4.2
CXX: /usr/bin/c++ => /usr/llvm-gcc-4.2/bin/llvm-g++-4.2
LD: /usr/bin/cc => /usr/llvm-gcc-4.2/bin/llvm-gcc-4.2
CFLAGS: -O3 -march=core2 -msse4.1 -w -pipe
CXXFLAGS: -O3 -march=core2 -msse4.1 -w -pipe

Error: Failed executing: make install 
Please report this bug: https://github.com/mxcl/homebrew/wiki/Checklist-before-filing-a-new-issue
These existing issues may help you:
https://github.com/mxcl/homebrew/issues/#issue/5254
https://github.com/mxcl/homebrew/issues/#issue/5445
https://github.com/mxcl/homebrew/issues/#issue/5597
https://github.com/mxcl/homebrew/issues/#issue/5603
https://github.com/mxcl/homebrew/issues/#issue/6043
https://github.com/mxcl/homebrew/issues/#issue/6473
https://github.com/mxcl/homebrew/issues/#issue/7024

Also try:
  `brew doctor` to check your setup for common problems.
  `brew missing` to check installed packages for missing deps.
-> % cd /Users/developer/Library/Caches/Homebrew/io--git/libs/basekit/source/    
developer@mbp13 [03:09:25] [~/Library/Caches/Homebrew/io--git/libs/basekit/source] [master]
-> % git st
# On branch master
# Your branch is behind 'origin/master' by 2158 commits, and can be fast-forwarded.
#
nothing to commit (working directory clean)
developer@mbp13 [03:09:32] [~/Library/Caches/Homebrew/io--git/libs/basekit/source] [master]
-> % git pull
Updating 32536d8..f345d7a
Fast-forward
 .gitignore                                         |    2 +
 README.md                                          |    5 +-
 addons/Box/io/Vector.io                            |    4 +-
 addons/Box/source/IoBox.c                          |    6 +-
 addons/CMakeLists.txt                              |    4 +-
 addons/Memcached/source/IoMemcached.c              |   13 +-
 addons/ObjcBridge/CMakeLists.txt                   |    6 +-
 addons/ObjcBridge/depends                          |    2 +
 addons/ObjcBridge/io/ObjcBridge.io                 |  192 +-
 addons/ObjcBridge/io/ObjcSyntax.io                 |  121 +
 addons/ObjcBridge/source/Io2Objc.h                 |    3 +
 addons/ObjcBridge/source/Io2Objc.m                 |  141 +-
 addons/ObjcBridge/source/IoLanguage.h              |    8 +
 addons/ObjcBridge/source/IoLanguage.m              |  133 +-
 addons/ObjcBridge/source/IoObjcBridge.h            |    3 +
 addons/ObjcBridge/source/IoObjcBridge.m            |  108 +-
 addons/ObjcBridge/source/Objc2Io.h                 |   10 +
 addons/ObjcBridge/source/Objc2Io.m                 |   51 +-
 addons/Socket/io/A0_EventManager.io                |    7 +-
 addons/Socket/source/Address.c                     |    2 +-
 addons/Socket/source/IPAddress.c                   |    2 +-
 addons/Socket/source/IoDNS.c                       |    4 +-
 addons/Socket/source/IoEvConnection.c              |    6 +-
 addons/Socket/source/IoEvConnection.h              |    4 +-
 addons/Socket/source/IoEvHttpServer.c              |    6 +-
 addons/Socket/source/IoEvOutRequest.c              |   17 +-
 addons/Socket/source/IoEvOutRequest.h              |    4 +
 addons/Socket/source/IoEvOutResponse.c             |    6 +-
 addons/Socket/source/IoEvent.c                     |    9 +-
 addons/Socket/source/IoEventManager.c              |    6 +-
 addons/Socket/source/IoIPAddress.c                 |    6 +-
 addons/Socket/source/IoSocket.c                    |    8 +-
 addons/Socket/source/IoUnixPath.c                  |    6 +-
 addons/SystemCall/io/SystemCall.io                 |   96 +-
 addons/SystemCall/source/IoSystemCall.c            |    8 +-
 addons/SystemCall/source/callsystem.c              |    4 +-
 addons/Yajl/CMakeLists.txt                         |    4 +-
 addons/Yajl/source/IoYajl.c                        |   13 +-
 addons/Yajl/source/IoYajlGen.c                     |   48 +-
 build/CPackConfig.cmake                            |   82 -
 build/CPackSourceConfig.cmake                      |   89 -
 extras/IoLanguageKit/IoLangKit.h                   |   13 -
 extras/IoLanguageKit/IoLangKit.m                   |   24 -
 extras/IoLanguageKit/IoLanguageKit.h               |    6 +
 .../IoLanguageKit.xcodeproj/project.pbxproj        |  Bin 109415 -> 132970 bytes
 .../UserInterfaceState.xcuserstate                 |13492 +++----
 extras/IoTest/IoTest.xcodeproj/project.pbxproj     |  Bin 14522 -> 15286 bytes
 .../UserInterfaceState.xcuserstate                 |47258 ++++++++++++++++++--
 .../xcdebugger/Breakpoints.xcbkptlist              |  260 +-
 extras/IoTest/IoTest/IoBrowserController.h         |   34 +
 extras/IoTest/IoTest/IoBrowserController.m         |  113 +
 extras/IoTest/IoTest/IoCLIController.h             |   14 +
 extras/IoTest/IoTest/IoCLIController.m             |   58 +
 extras/IoTest/IoTest/IoTestAppDelegate.h           |   17 -
 extras/IoTest/IoTest/IoTestAppDelegate.m           |   82 -
 extras/IoTest/IoTest/en.lproj/MainMenu.xib         |  222 +-
 libs/basekit/source/Common_inline.h                |  130 +-
 libs/basekit/source/UArray.c                       |   10 +-
 libs/basekit/source/UArray.h                       |   10 +-
 libs/basekit/source/UArray_math.c                  |   16 +-
 libs/iovm/io/A4_Exception.io                       |    2 +-
 libs/iovm/io/B_Sequence.io                         |    8 +-
 libs/iovm/source/IoFile.c                          |    1 +
 libs/iovm/source/IoMessage.c                       |    1 +
 libs/iovm/source/IoObject.c                        |    4 +-
 libs/iovm/source/IoSeq.c                           |    8 +
 libs/iovm/source/IoSeq.h                           |    1 +
 libs/iovm/source/IoState.c                         |    5 +-
 68 files changed, 51026 insertions(+), 12012 deletions(-)
 create mode 100644 addons/ObjcBridge/io/ObjcSyntax.io
 delete mode 100644 build/CPackConfig.cmake
 delete mode 100644 build/CPackSourceConfig.cmake
 delete mode 100644 extras/IoLanguageKit/IoLangKit.h
 delete mode 100644 extras/IoLanguageKit/IoLangKit.m
 create mode 100644 extras/IoLanguageKit/IoLanguageKit.h
 create mode 100644 extras/IoTest/IoTest/IoBrowserController.h
 create mode 100644 extras/IoTest/IoTest/IoBrowserController.m
 create mode 100644 extras/IoTest/IoTest/IoCLIController.h
 create mode 100644 extras/IoTest/IoTest/IoCLIController.m
 delete mode 100644 extras/IoTest/IoTest/IoTestAppDelegate.h
 delete mode 100644 extras/IoTest/IoTest/IoTestAppDelegate.m
developer@mbp13 [03:09:39] [~/Library/Caches/Homebrew/io--git/libs/basekit/source] [master]
-> % brew install io
==> Cloning https://github.com/stevedekorte/io.git
Updating /Users/developer/Library/Caches/Homebrew/io--git
==> Downloading patches
==> Patching
patching file addons/Image/CMakeLists.txt
==> cmake .. -DCMAKE_INSTALL_PREFIX='/usr/local/Cellar/io/HEAD' -DCMAKE_BUILD_TYPE=None -Wno-dev
==> make install
/usr/local/Cellar/io/HEAD: 1834 files, 20M, built in 93 seconds
developer@mbp13 [03:11:53] [~/Library/Caches/Homebrew/io--git/libs/basekit/source] [master]
-> % 

Line 10 runs a fetch only and I have not yet traced where a pull is attempted, if at all, when a repo already exists.