cmd/cgo: invalid flag in #cgo CFLAGS: -w

[Aukstkalnis]

What did you do?

I tried to build simple gui app using sciter: https://github.com/sciter-sdk/go-sciter

What did you expect to see?

Successful build.

What did you see instead?

cgo error:
github.com/sciter-sdk/go-sciter: invalid flag in #cgo CFLAGS: -w
The terminal process terminated with exit code: 1

With 1.9.4 version there was no such error. I tried using CGO_CFLAGS_ALLOW = 1, but that didn't worked for me.

System details

go version go1.10 windows/amd64
GOARCH="amd64"
GOBIN=""
GOCACHE="%USER%\AppData\Local\go-build"
GOEXE=".exe"
GOHOSTARCH="amd64"
GOHOSTOS="windows"
GOOS="windows"
GOPATH="D:\Projects\Go_Projects"
GORACE=""
GOROOT="C:\go"
GOTMPDIR=""
GOTOOLDIR="C:\go\pkg\tool\windows_amd64"
GCCGO="gccgo"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-m64 -mthreads -fmessage-length=0 -fdebug-prefix-map=D:\Temp\go-build589517054=/tmp/go-build -gno-record-gcc-switches"
GOROOT/bin/go version: go version go1.10 windows/amd64
GOROOT/bin/go tool compile -V: compile version go1.10
lldb --version: lldb version 5.0.0
gdb --version: GNU gdb (GDB) 8.0

[AlexRouSg]

https://github.com/golang/go/wiki/InvalidFlag

Set the environment variable CGO_CFLAGS_ALLOW (or CGO_LDFLAGS_ALLOW, CGO_CXXFLAGS_ALLOW, and so forth) to a regexp that matches the option.

CGO_CFLAGS_ALLOW Is not a boolean, it is a string regexp.

[ianlancetaylor]

Consolidating into #23937.