Fixed a few warnings.

Rev: src/array.c:1.86
Rev: src/docode.c:1.81
Rev: src/interpret.c:1.170
Rev: src/mapping.c:1.102
Rev: src/modules/Image/encodings/gif_lzw.c:1.9
Rev: src/modules/Odbc/odbc_result.c:1.23
Rev: src/modules/Regexp/pike_regexp.c:1.17
Rev: src/modules/_Image_JPEG/image_jpeg.c:1.35
Rev: src/modules/_Image_TTF/image_ttf.c:1.35
Rev: src/modules/_Image_XFace/image_xface.c:1.11
Rev: src/pike_memory.c:1.83
Rev: src/pike_types.c:1.138