cmd/cgo: avoid C++ style comments
cmd/cgo: avoid C++ style comments

Change-Id: I9d399db8ac26ad44adeace3bf1e5b11cbfe3e0d3
Reviewed-on: https://go-review.googlesource.com/41313
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
Run-TryBot: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

Cofyc/go,akutz/go,vsekhar/elastic-go,vsekhar/elastic-go,josharian/go,ImJasonH/go,Cofyc/go,cloudflare/go,Cofyc/go,CAFxX/go,nawawi/go,vsekhar/elastic-go,derekmarcotte/go,nawawi/go,vsekhar/elastic-go,ImJasonH/go,derekmarcotte/go,Cofyc/go,polyverse-security/go,ImJasonH/go,cloudflare/go,Cofyc/go,Cofyc/go,josharian/go,cloudflare/go,cloudflare/go,codestation/go,golang/go,CAFxX/go,akutz/go,golang/go,vsekhar/elastic-go,nawawi/go,polyverse-security/go,polyverse-security/go,CAFxX/go,polyverse-security/go,derekmarcotte/go,golang/go,josharian/go,golang/go,polyverse-security/go,ImJasonH/go,codestation/go,vsekhar/elastic-go,vsekhar/elastic-go,Cofyc/go,josharian/go,cloudflare/go,ImJasonH/go,codestation/go,golang/go,golang/go,ImJasonH/go,derekmarcotte/go,nawawi/go,nawawi/go,derekmarcotte/go,codestation/go,derekmarcotte/go,nawawi/go,CAFxX/go,golang/go,codestation/go,CAFxX/go,codestation/go,cloudflare/go,josharian/go,cloudflare/go,nawawi/go,akutz/go,polyverse-security/go,nawawi/go,derekmarcotte/go,josharian/go,akutz/go,vsekhar/elastic-go,golang/go,polyverse-security/go,josharian/go,polyverse-security/go,codestation/go,CAFxX/go,CAFxX/go,christopher-henderson/Go,Cofyc/go,akutz/go,akutz/go,CAFxX/go,codestation/go,ImJasonH/go,derekmarcotte/go,josharian/go,cloudflare/go,akutz/go,ImJasonH/go,akutz/go