Update-alternatives errors when installing clang or ghc

["ThanhVu (Vu) Nguyen" <nguyenthanhvuh@gmail.com>]

When doing apt-get install clang (or ghc) on Debian Jessie 8 ,  I got the following errors with update-alternatives.  Is there something wrong with my update-alternatives installation ?  

...

Setting up ghc (7.6.3-21) ...

update-alternatives: error: alternative path /usr/bin/runghc doesn't exist

dpkg: error processing package ghc (--configure):

 subprocess installed post-installation script returned error exit status 2

Setting up clang (1:3.5-25) ...

update-alternatives: error: alternative path /usr/bin/clang++ doesn't exist

dpkg: error processing package clang (--configure):

 subprocess installed post-installation script returned error exit status 2

Errors were encountered while processing:

 ghc

 clang

E: Sub-process /usr/bin/dpkg returned an error code (1)

.....

Setting up ghc (7.6.3-21) ...

update-alternatives: error: alternative path /usr/bin/runghc doesn't exist

dpkg: error processing package ghc (--configure):

 subprocess installed post-installation script returned error exit status 2

Setting up clang (1:3.5-25) ...

update-alternatives: error: alternative path /usr/bin/clang++ doesn't exist

dpkg: error processing package clang (--configure):

 subprocess installed post-installation script returned error exit status 2

Errors were encountered while processing:

 ghc

 clang

E: Sub-process /usr/bin/dpkg returned an error code (1)

Vu