[ptx] hugin and libpano build problems

[Rich]

when compiling libpano and hugin, i encountered a couple of problems.

1. configure fails when checking wether "png package is complete"
config.log shows that it stopped at "undefined reference to `pow'"
after some googleing it turned out that compiler flag -lm (to reference 
mathlib) was needed.
thus
export CFLAGS="-lm"; ./configure
works fine.

why isn't this flag added by default - and maybe it should be ?

this is slackware-current, gcc 3.3.5

2. boost location for hugin

hugin tried to find boost includes in 
<with-boost>/include/boost-<with-boost-version>

boost 1.32.0 has includes in root directory (of it's own tree), so there 
is no way to tell configure script how to find them.

the solution is editing configure script, line 24476 from
ac_boost_includedir="$withval/include/boost$BOOST_VERSION_"
to
ac_boost_includedir="$withval"

though this probably breaks support for boost 1.31.0
-- 
  Rich