Support for libz added

Rev: src/ChangeLog:1.19
Rev: src/configure.in:1.14
Rev: src/dynamic_buffer.c:1.2
Rev: src/dynamic_buffer.h:1.2
Rev: src/modules/files/file.c:1.12
Rev: src/modules/image/togif.c:1.12
Rev: src/modules/spider/encode_decode.c:1.4
Rev: src/modules/zlibmod/.cvsignore:1.1
Rev: src/modules/zlibmod/Makefile.src:1.1
Rev: src/modules/zlibmod/configure.in:1.1
Rev: src/modules/zlibmod/testsuite.in:1.1
Rev: src/modules/zlibmod/zlib_machine.h.in:1.1
Rev: src/modules/zlibmod/zlibmod.c:1.1
Rev: src/peep.c:1.3
Rev: src/program.c:1.7
Rev: src/program.h:1.3