cmd/cgo: do not use gcc -xc - to compile standard input
cmd/cgo: do not use gcc -xc - to compile standard input

We have private reports of compilers that mishandle that.
Write to a temporary file instead.

Change-Id: I92e3cf4274b1a8048741e07fb52b8900c93b915e
Reviewed-on: https://go-review.googlesource.com/19616
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

golang/go,Samurais/go,codestation/go,momchil-velikov/go,goodlang/good,cloudflare/go,linux-on-ibm-z/go,CAFxX/go,miolini/go,cloudflare/go,golang/go,momchil-velikov/go,miolini/go,linux-on-ibm-z/go,akutz/go,vanloswang/go,vanloswang/go,polyverse-security/go,momchil-velikov/go,derekmarcotte/go,mwhudson/go,Samurais/go,vanloswang/go,ImJasonH/go,josharian/go,4ad/go,josharian/go,miolini/go,4ad/go,golang/go,theif519/go,josharian/go,theif519/go,miolini/go,akutz/go,vanloswang/go,4ad/go,4ad/go,golang/go,CAFxX/go,CAFxX/go,theif519/go,golang/go,ImJasonH/go,polyverse-security/go,ImJasonH/go,vsekhar/elastic-go,derekmarcotte/go,codestation/go,CAFxX/go,ImJasonH/go,momchil-velikov/go,vsekhar/elastic-go,linux-on-ibm-z/go,christopher-henderson/Go,Samurais/go,goodlang/good,akutz/go,vanloswang/go,vanloswang/go,golang/go,polyverse-security/go,Cofyc/go,cloudflare/go,4ad/go,nawawi/go,mwhudson/go,theif519/go,binarycrusader/go,akutz/go,akutz/go,4ad/go,ImJasonH/go,goodlang/good,Cofyc/go,Cofyc/go,binarycrusader/go,mwhudson/go,vanloswang/go,derekmarcotte/go,goodlang/good,Cofyc/go,CAFxX/go,momchil-velikov/go,suncycheng/go,miolini/go,polyverse-security/go,codestation/go,linux-on-ibm-z/go,ganboing/go-esx,theif519/go,binarycrusader/go,nawawi/go,ganboing/go-esx,Cofyc/go,momchil-velikov/go,Samurais/go,cloudflare/go,binarycrusader/go,goodlang/good,binarycrusader/go,mwhudson/go,4ad/go,goodlang/good,codestation/go,polyverse-security/go,nawawi/go,vsekhar/elastic-go,momchil-velikov/go,ganboing/go-esx,ImJasonH/go,linux-on-ibm-z/go,cloudflare/go,CAFxX/go,vsekhar/elastic-go,vanloswang/go,codestation/go,CAFxX/go,miolini/go,ganboing/go-esx,ganboing/go-esx,derekmarcotte/go,vsekhar/elastic-go,josharian/go,akutz/go,ganboing/go-esx,Samurais/go,Samurais/go,golang/go,Cofyc/go,polyverse-security/go,theif519/go,Cofyc/go,akutz/go,suncycheng/go,theif519/go,codestation/go,Samurais/go,vsekhar/elastic-go,nawawi/go,goodlang/good,binarycrusader/go,binarycrusader/go,akutz/go,polyverse-security/go,suncycheng/go,codestation/go,nawawi/go,goodlang/good,theif519/go,cloudflare/go,suncycheng/go,mwhudson/go,josharian/go,suncycheng/go,miolini/go,Cofyc/go,derekmarcotte/go,golang/go,josharian/go,mwhudson/go,mwhudson/go,nawawi/go,codestation/go,josharian/go,cloudflare/go,ganboing/go-esx,ImJasonH/go,cloudflare/go,derekmarcotte/go,4ad/go,derekmarcotte/go,linux-on-ibm-z/go,ImJasonH/go,nawawi/go,vsekhar/elastic-go,Samurais/go,nawawi/go,polyverse-security/go,josharian/go,CAFxX/go,mwhudson/go,suncycheng/go,ganboing/go-esx,momchil-velikov/go,derekmarcotte/go,suncycheng/go,vsekhar/elastic-go,linux-on-ibm-z/go,suncycheng/go,binarycrusader/go,miolini/go,linux-on-ibm-z/go