hs-json @0.4.4 configure fails

[macports@…]

When hs-json is installed as a dependency of pandoc, its configure step fails reporting:

Setup: At least the following dependencies are missing:
mtl -any

I'm running OS X 10.8.1 and XCode 4.4.1

port log file:

:notice:configure --->  Configuring hs-json
:debug:configure Using compiler 'Mac OS X clang'
:debug:configure Executing org.macports.configure (hs-json)
:debug:configure Environment: CPATH='/opt/local/include' CFLAGS='-pipe -O2 -arch x86_64' CPPFLAGS='-I/opt/local/include' CXXFLAGS='-pipe -O2 -arch x86_64' LIBRARY_PATH='/opt/local/lib' MACOSX_DEPLOYMENT_TARGET='10.8' CXX='/usr/bin/clang++' CC_PRINT_OPTIONS_FILE='/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_devel_hs-json/hs-json/work/.CC_PRINT_OPTIONS' F90FLAGS='-pipe -O2 -m64' LDFLAGS='-L/opt/local/lib -arch x86_64' OBJC='/usr/bin/clang' FCFLAGS='-pipe -O2 -m64' INSTALL='/usr/bin/install -c' OBJCFLAGS='-pipe -O2 -arch x86_64' FFLAGS='-pipe -O2 -m64' CC_PRINT_OPTIONS='YES' CC='/usr/bin/clang'
:debug:configure Assembled command: 'cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_devel_hs-json/hs-json/work/json-0.4.4" && runhaskell Setup configure --prefix=/opt/local --with-compiler=/opt/local/bin/ghc'
:debug:configure Executing command line:  cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_devel_hs-json/hs-json/work/json-0.4.4" && runhaskell Setup configure --prefix=/opt/local --with-compiler=/opt/local/bin/ghc 
:info:configure Configuring json-0.4.4...
:info:configure Setup: At least the following dependencies are missing:
:info:configure mtl -any
:info:configure Command failed:  cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_devel_hs-json/hs-json/work/json-0.4.4" && runhaskell Setup configure --prefix=/opt/local --with-compiler=/opt/local/bin/ghc 
:info:configure Exit code: 1
:error:configure org.macports.configure for port hs-json returned: configure failure: command execution failed
:debug:configure Error code: NONE
:debug:configure Backtrace: configure failure: command execution failed
    while executing
"$procedure $targetname"
:info:configure Warning: targets not executed for hs-json: org.macports.activate org.macports.configure org.macports.build org.macports.destroot org.macports.install
:error:configure Failed to install hs-json
:debug:configure couldn't open "/System/Library/Frameworks/Tcl.framework/Versions/8.5/Resources/tclIndex": no such file or directory
    while executing
"open [file join $dir tclIndex]"

[ryandesign (Ryan Carsten Schmidt)]

A dependency on hs-mlt was added in r97989.

However it's reported in #36377 that there's still a problem finding it.