std::vec: Use a valid value as lifetime dummy in iterator
std::vec: Use a valid value as lifetime dummy in iterator

The current implementation uses `&v[0]` for the lifetime struct field,
but that is a dangling pointer for iterators derived from zero-length
slices.

Example:

    let v: [int, ..0] = [];  println!("{:?}", v.iter())

    std::vec::VecIterator<,int>{ptr: (0x7f3768626100 as *()), end: (0x7f3768626100 as *()), lifetime: &139875951207128}

To replace this parameter, use a field of type `Option<&'self ()>`
that is simply initialized with `None`, but still allows the iterator to
have a lifetime parameter.

ktossell/rust,jbclements/rust,sae-bom/rust,jroesch/rust,KokaKiwi/rust,XMPPwocky/rust,ebfull/rust,carols10cents/rust,avdi/rust,michaelballantyne/rust-gpu,Ryman/rust,ebfull/rust,pshc/rust,aturon/rust,jbclements/rust,zaeleus/rust,jbclements/rust,stepancheg/rust-ide-rust,sae-bom/rust,zubron/rust,hauleth/rust,Ryman/rust,TheNeikos/rust,kwantam/rust,GBGamer/rust,stepancheg/rust-ide-rust,jroesch/rust,untitaker/rust,carols10cents/rust,XMPPwocky/rust,reem/rust,AerialX/rust,erickt/rust,fabricedesre/rust,avdi/rust,nham/rust,0x73/rust,SiegeLord/rust,philyoon/rust,seanrivera/rust,seanrivera/rust,miniupnp/rust,cllns/rust,servo/rust,aepsil0n/rust,richo/rust,mihneadb/rust,LeoTestard/rust,jroesch/rust,reem/rust,cllns/rust,ebfull/rand,jroesch/rust,emk/rust,rohitjoshi/rust,bluss/rand,hauleth/rust,andars/rust,victorvde/rust,gifnksm/rust,AerialX/rust,dwillmer/rust,aidancully/rust,servo/rust,erickt/rust,dwillmer/rust,achanda/rand,TheNeikos/rust,bombless/rust,untitaker/rust,nham/rust,barosl/rust,defuz/rust,zubron/rust,nwin/rust,mdinger/rust,P1start/rust,nwin/rust,pelmers/rust,jbclements/rust,quornian/rust,omasanori/rust,KokaKiwi/rust,pythonesque/rust,mvdnes/rust,vhbit/rust,mihneadb/rust,ebfull/rust,kimroen/rust,mihneadb/rust,aidancully/rust,cllns/rust,pelmers/rust,bombless/rust,ktossell/rust,mahkoh/rust,fabricedesre/rust,stepancheg/rust-ide-rust,pshc/rust,KokaKiwi/rust,omasanori/rust,mvdnes/rust,jashank/rust,carols10cents/rust,pshc/rust,aepsil0n/rust,rprichard/rust,zachwick/rust,rprichard/rust,shepmaster/rand,aneeshusa/rust,aturon/rust,omasanori/rust,robertg/rust,emk/rust,fabricedesre/rust,GrahamDennis/rand,avdi/rust,zachwick/rust,nwin/rust,SiegeLord/rust,nham/rust,mvdnes/rust,victorvde/rust,nwin/rust,vhbit/rust,omasanori/rust,Ryman/rust,michaelballantyne/rust-gpu,sae-bom/rust,rprichard/rust,GBGamer/rust,mihneadb/rust,carols10cents/rust,P1start/rust,pshc/rust,untitaker/rust,zachwick/rust,l0kod/rust,l0kod/rust,huonw/rand,pythonesque/rust,retep998/rand,krzysz00/rust,krzysz00/rust,SiegeLord/rust,graydon/rust,zaeleus/rust,mitsuhiko/rust,barosl/rust,pelmers/rust,miniupnp/rust,jashank/rust,gifnksm/rust,KokaKiwi/rust,AerialX/rust-rt-minimal,hauleth/rust,gifnksm/rust,omasanori/rust,defuz/rust,aidancully/rust,robertg/rust,GBGamer/rust,jroesch/rust,nham/rust,aidancully/rust,stepancheg/rust-ide-rust,ejjeong/rust,AerialX/rust,ejjeong/rust,aturon/rust,bombless/rust-docs-chinese,omasanori/rust,emk/rust,AerialX/rust-rt-minimal,victorvde/rust,LeoTestard/rust,LeoTestard/rust,quornian/rust,andars/rust,aepsil0n/rust,seanrivera/rust,victorvde/rust,nham/rust,aidancully/rust,erickt/rust,zubron/rust,reem/rust,erickt/rust,mitsuhiko/rust,TheNeikos/rust,zachwick/rust,mvdnes/rust,vhbit/rust,jashank/rust,aepsil0n/rust,vhbit/rust,richo/rust,AerialX/rust,cllns/rust,andars/rust,kimroen/rust,LeoTestard/rust,pshc/rust,l0kod/rust,aturon/rust,hauleth/rust,cllns/rust,servo/rust,dinfuehr/rust,AerialX/rust-rt-minimal,GBGamer/rust,defuz/rust,aidancully/rust,graydon/rust,aneeshusa/rust,SiegeLord/rust,carols10cents/rust,jbclements/rust,quornian/rust,krzysz00/rust,l0kod/rust,ruud-v-a/rust,graydon/rust,jashank/rust,fabricedesre/rust,GBGamer/rust,XMPPwocky/rust,waynenilsen/rand,miniupnp/rust,bombless/rust,stepancheg/rust-ide-rust,miniupnp/rust,hauleth/rust,zaeleus/rust,michaelballantyne/rust-gpu,mahkoh/rust,erickt/rust,P1start/rust,pythonesque/rust,miniupnp/rust,defuz/rust,stepancheg/rust-ide-rust,TheNeikos/rust,pshc/rust,vhbit/rust,erickt/rust,emk/rust,pythonesque/rust,mdinger/rust,ebfull/rust,quornian/rust,AerialX/rust-rt-minimal,l0kod/rust,servo/rust,pshc/rust,nwin/rust,ruud-v-a/rust,zubron/rust,untitaker/rust,kimroen/rust,barosl/rust,aneeshusa/rust,0x73/rust,rohitjoshi/rust,emk/rust,untitaker/rust,dwillmer/rust,KokaKiwi/rust,nham/rust,pythonesque/rust,robertg/rust,zubron/rust,mahkoh/rust,pczarn/rust,seanrivera/rust,rprichard/rust,ejjeong/rust,dinfuehr/rust,SiegeLord/rust,0x73/rust,aepsil0n/rust,pythonesque/rust,defuz/rust,SiegeLord/rust,fabricedesre/rust,dwillmer/rust,mitsuhiko/rust,andars/rust,avdi/rust,jbclements/rust,ktossell/rust,sae-bom/rust,krzysz00/rust,jashank/rust,jbclements/rust,pczarn/rust,jroesch/rust,philyoon/rust,zubron/rust,dwillmer/rust,zachwick/rust,reem/rust,nwin/rust,P1start/rust,pczarn/rust,ejjeong/rust,graydon/rust,mitsuhiko/rust,zaeleus/rust,l0kod/rust,michaelballantyne/rust-gpu,defuz/rust,miniupnp/rust,michaelballantyne/rust-gpu,rohitjoshi/rust,zubron/rust,GBGamer/rust,philyoon/rust,mahkoh/rust,pythonesque/rust,TheNeikos/rust,dinfuehr/rust,zachwick/rust,kwantam/rust,GBGamer/rust,pshc/rust,dinfuehr/rust,P1start/rust,AerialX/rust,kimroen/rust,AerialX/rust-rt-minimal,mitsuhiko/rust,quornian/rust,rohitjoshi/rust,vhbit/rust,pczarn/rust,mahkoh/rust,zaeleus/rust,pczarn/rust,ebfull/rust,robertg/rust,gifnksm/rust,quornian/rust,rprichard/rust,victorvde/rust,jroesch/rust,philyoon/rust,sae-bom/rust,P1start/rust,ejjeong/rust,servo/rust,dwillmer/rust,KokaKiwi/rust,philyoon/rust,stepancheg/rust-ide-rust,barosl/rust,mihneadb/rust,vhbit/rust,jroesch/rust,0x73/rust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