After switching from PHP 3.0.7 to PHP 3.0.11 I found out that ltrim() behaves much like
trim() e.g. it strips newlines (maybe whitespace as well) from the _end_ of the supplied string 
as well. I put up a test script at http://uf.kadan.cz/~pallas/ltrimtest.php3 and its source at
http://uf.kadan.cz/~pallas/ltrimtest.phps. The script produces the same result in browser, but
if you look at the page source, you can clearly see, that the newlines have been stripped where 
ltrim() was applied. For more information about PHP environment, I've put up a phpinfo() at
http://uf.kadan.cz/~pallas/info.php3. I hope it's enough information provided.

I configured PHP using the following configuration line:

configure \
  --with-zlib \
  --with-gd \
  --with-gdbm \
  --with-pgsql=/opt/postgres \
  --with-shared-apache=../apache_1.3.6 \
  --with-exec-dir=/home/httpd/CGI \
  --enable-track-vars=yes