Merge pull request leanprover-community#22 from goens/linux-build

Add PIC for Linux builds

lakefile.lean

@@ -14,7 +14,7 @@ target importTarget pkg : FilePath := do
   let oFile := pkg.buildDir / "c" / "ffi.o"
   let srcJob ← inputFile <| pkg.dir / "C" / "ffi.c"
   buildFileAfterDep oFile srcJob fun srcFile => do
-    let flags := #["-I", toString (← getLeanIncludeDir)]
+    let flags := #["-I", toString (← getLeanIncludeDir), "-fPIC"]
     compileO "ffi.c" oFile srcFile flags
 
 extern_lib ffi pkg := do
@@ -23,7 +23,7 @@ extern_lib ffi pkg := do
   buildStaticLib libFile #[job]
 
 extern_lib egg_for_lean pkg := do
-  proc { cmd := "cargo", args := #["build", "--release"], cwd := pkg.dir / "Rust" }
+  proc { cmd := "cargo", args := #["rustc", "--release", "--", "-C", "relocation-model=pic"], cwd := pkg.dir / "Rust" }
   let name := nameToStaticLib "egg_for_lean"
   let srcPath := pkg.dir / "Rust" / "target" / "release" / name
   IO.FS.createDirAll pkg.nativeLibDir