[REVIEW-3-5] --enable-python=internal build fix

[Stephan Bergmann]

Without 
<http://cgit.freedesktop.org/libreoffice/core/commit/?id=7d8f3b19c69e741175bed035681cfacd3a30713d> 
"Linux LD_LIBRARY_PATH is missing as well.", --enable-python=internal 
fails to build on Linux.

Would be nice to have that fix in -3-5 as well (but no need for -3-5-3).

Thanks,
Stephan