Request for RISC-V Architecture Support

[hawkli-1994]

Description:
I'm attempting to cross-compile JuiceFS for RISC-V (riscv64) architecture but encountering build failures due to incompatible dependencies. The following packages appear to have build constraints excluding RISC-V:

1. github.com/erikdubbelboer/gspt
2. github.com/hungys/go-lz4
3. github.com/DataDog/zstd

Error message:

build constraints exclude all Go files in ...

Reproduction Steps:

1. Set up Go cross-compilation environment for riscv64
2. Run:

   CGO_ENABLED=0 GOARCH=riscv64 go build -v -tags nosqlite \
     -ldflags="-s -w -X github.com/juicedata/juicefs/pkg/version.revision=... \
     -X github.com/juicedata/juicefs/pkg/version.revisionDate=..." \
     -o juicefs.riscv .

Expected Behavior:
Successful compilation for riscv64 architecture

Actual Behavior:
Build fails due to unsupported architecture in dependencies

Suggested Solutions:

1. Evaluate alternative packages that support RISC-V:

   • Replace go-lz4 with github.com/pierrec/lz4
   • Replace DataDog/zstd with github.com/klauspost/compress/zstd

2. Add riscv64 to build constraints for critical dependencies

3. Consider maintaining a riscv64 compatible build tag

Additional Context:
RISC-V is gaining significant adoption in edge computing and embedded systems where JuiceFS could provide valuable distributed storage capabilities. Official support would enable JuiceFS deployment in these growing ecosystems.

Environment:

• Go version: [1.23]
• OS: [Ubuntu]
• Architecture: riscv64 (cross-compiling from [x86_64])

[jiefenghuang]

you can try #6186 with CGO_ENABLED=1 CC=riscv64-linux-gnu-gcc