Checking if your kit is complete...
Looks good
Warning: -L./ changed to -L/home/cpanrun/depot/main/contrib-patched/perl/CPAN/src/Net-Gadu/./
Note (probably harmless): No library found for -lgadu
Writing Makefile for Net::Gadu
cp Gadu.pm blib/lib/Net/Gadu.pm
AutoSplitting blib/lib/Net/Gadu.pm (blib/lib/auto/Net/Gadu)
/home/cpanrun/build/5.6.1/bin/perl -I/home/cpanrun/build/5.6.1/lib/5.6.1/i686-linux-thread-multi -I/home/cpanrun/build/5.6.1/lib/5.6.1 /home/cpanrun/build/5.6.1/lib/5.6.1/ExtUtils/xsubpp  -typemap /home/cpanrun/build/5.6.1/lib/5.6.1/ExtUtils/typemap -typemap typemap Gadu.xs > Gadu.xsc && mv Gadu.xsc Gadu.c
gcc -c -I/usr/include -I/usr/local/include -L./ -DUSE_REENTRANT_API -D_GNU_SOURCE -D_REENTRANT -fno-strict-aliasing -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -O2   -DVERSION=\"1.7\" -DXS_VERSION=\"1.7\" -fpic -I/home/cpanrun/build/5.6.1/lib/5.6.1/i686-linux-thread-multi/CORE  Gadu.c
Gadu.xs:25: libgadu.h: No such file or directory
make: *** [Gadu.o] Error 1