all calls to open(2) now handles EINTR

Rev: src/interpret.c:1.10
Rev: src/modules/files/file.c:1.13
Rev: src/modules/image/font.c:1.7
Rev: src/modules/spider/sharedmem.c:1.5
Rev: src/program.c:1.8
Rev: src/rusage.c:1.3