[tlbuild] ptexenc patch

[Karl Berry]

Hi Ken,

    I'm working with one of the Cygwin developers to package TeX Live for 
    the Cygwin distribution.  So I'm using the configure options 
    --enable-shared and --disable-native-texlive-build.

I'm never surprised when for-the-system builds fail.

    In this setting the build in ptexenc fails because of undefined
    symbols that should be found in the kpathsea library.  

We need Akira's, or someone's, input.
(I'm a bit surprised this was not necessary all along.)

    The attached patch fixes the problem.  As usual, I don't know
    whether this is the right way to fix it.

I'm not sure about adding it to *lib*ptexenc, shouldn't KPATHSEA_LIBS be
relevant to the executable, not the library?
But anyway, it's at least a lot more plausible than
LDADD = ... -lpaper
:).

Thanks,
karl

+++ src/texlive-20110705-source/texk/ptexenc/Makefile.am	2012-01-17 15:02:38.059249300 -0600
..
+libptexenc_la_LIBADD = $(KPATHSEA_LIBS)