net: '_GNU_SOURCE' macro redefined in net package when building TinyGo on Linux #66325
Description
Go version
go version go1.22.1 linux/amd64
Output of go env in your module/workspace:
GO111MODULE=''
GOARCH='amd64'
GOBIN=''
GOCACHE='/home/b/.cache/go-build'
GOENV='/home/b/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMODCACHE='/home/b/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/b/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/home/b/git/go1.22'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/home/b/git/go1.22/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.22.1'
GCCGO='gccgo'
GOAMD64='v1'
AR='ar'
CC='clang-17'
CXX='clang++-17'
CGO_ENABLED='1'
GOMOD='/home/b/git/tinygo/go.mod'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build502953574=/tmp/go-build -gno-record-gcc-switches'What did you do?
I built TinyGo and got a warning.
To reproduce checkout and build TinyGo
$ git log --oneline -1
6384ecac (HEAD -> dev, tag: v0.31.2, upstream/release, upstream/dev, upstream/HEAD, origin/release, origin/libc-noescape, origin/dev, libc-noescape) docs: update CHANGELOG for 0.31.2 patch releaseWhat did you see happen?
warning is at end of output:
$ make tinygo
CGO_CPPFLAGS="-I/home/b/git/tinygo/llvm-project/llvm/include -I/home/b/git/tinygo/llvm-build/include -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/b/git/tinygo/llvm-build/tools/clang/include -I/home/b/git/tinygo/llvm-project/clang/include -I/home/b/git/tinygo/llvm-project/lld/include" CGO_CXXFLAGS="-std=c++17" CGO_LDFLAGS="-L/home/b/git/tinygo/llvm-build/lib -lclang -Wl,--start-group -lclangAnalysis -lclangAST -lclangASTMatchers -lclangBasic -lclangCodeGen -lclangCrossTU -lclangDriver -lclangDynamicASTMatchers -lclangEdit -lclangExtractAPI -lclangFormat -lclangFrontend -lclangFrontendTool -lclangHandleCXX -lclangHandleLLVM -lclangIndex -lclangLex -lclangParse -lclangRewrite -lclangRewriteFrontend -lclangSema -lclangSerialization -lclangSupport -lclangTooling -lclangToolingASTDiff -lclangToolingCore -lclangToolingInclusions -Wl,--end-group -lstdc++ -Wl,--start-group -llldCOFF -llldCommon -llldELF -llldMachO -llldMinGW -llldWasm -Wl,--end-group -L/home/b/git/tinygo/llvm-build/lib -lLLVMWindowsManifest -lLLVMWindowsDriver -lLLVMMCJIT -lLLVMLTO -lLLVMPasses -lLLVMIRPrinter -lLLVMExtensions -lLLVMLibDriver -lLLVMOption -lLLVMInterpreter -lLLVMFrontendHLSL -lLLVMExecutionEngine -lLLVMRuntimeDyld -lLLVMOrcTargetProcess -lLLVMOrcShared -lLLVMCoverage -lLLVMCoroutines -lLLVMXtensaDisassembler -lLLVMXtensaAsmParser -lLLVMXtensaCodeGen -lLLVMXtensaDesc -lLLVMXtensaInfo -lLLVMAVRDisassembler -lLLVMAVRAsmParser -lLLVMAVRCodeGen -lLLVMAVRDesc -lLLVMAVRInfo -lLLVMWebAssemblyDisassembler -lLLVMWebAssemblyAsmParser -lLLVMWebAssemblyCodeGen -lLLVMWebAssemblyUtils -lLLVMWebAssemblyDesc -lLLVMWebAssemblyInfo -lLLVMRISCVTargetMCA -lLLVMRISCVDisassembler -lLLVMRISCVAsmParser -lLLVMRISCVCodeGen -lLLVMRISCVDesc -lLLVMRISCVInfo -lLLVMAArch64Disassembler -lLLVMAArch64AsmParser -lLLVMAArch64CodeGen -lLLVMAArch64Desc -lLLVMAArch64Utils -lLLVMAArch64Info -lLLVMARMDisassembler -lLLVMARMAsmParser -lLLVMARMCodeGen -lLLVMipo -lLLVMVectorize -lLLVMLinker -lLLVMFrontendOpenMP -lLLVMARMDesc -lLLVMARMUtils -lLLVMARMInfo -lLLVMX86TargetMCA -lLLVMMCA -lLLVMX86Disassembler -lLLVMX86AsmParser -lLLVMX86CodeGen -lLLVMX86Desc -lLLVMX86Info -lLLVMMCDisassembler -lLLVMInstrumentation -lLLVMGlobalISel -lLLVMSelectionDAG -lLLVMCFGuard -lLLVMAsmPrinter -lLLVMCodeGen -lLLVMTarget -lLLVMScalarOpts -lLLVMInstCombine -lLLVMAggressiveInstCombine -lLLVMObjCARCOpts -lLLVMTransformUtils -lLLVMCodeGenTypes -lLLVMBitWriter -lLLVMAnalysis -lLLVMProfileData -lLLVMSymbolize -lLLVMDebugInfoBTF -lLLVMDebugInfoPDB -lLLVMDebugInfoMSF -lLLVMDebugInfoDWARF -lLLVMObject -lLLVMTextAPI -lLLVMMCParser -lLLVMIRReader -lLLVMAsmParser -lLLVMMC -lLLVMDebugInfoCodeView -lLLVMBitReader -lLLVMCore -lLLVMRemarks -lLLVMBitstreamReader -lLLVMBinaryFormat -lLLVMTargetParser -lLLVMSupport -lLLVMDemangle -lrt -ldl -lm -lstdc++ " go build -buildmode exe -o build/tinygo -tags "byollvm osusergo" -ldflags="-X github.com/tinygo-org/tinygo/goenv.GitSha1=`git rev-parse --short HEAD`" .
# net
../go1.22/src/net/cgo_unix_cgo.go:10:9: warning: '_GNU_SOURCE' macro redefined [-Wmacro-redefined]
<command line>:1:9: note: previous definition is hereWhat did you expect to see?
Expected to see no warning from Go standard library file src/net/cgo_unix_cgo.go