feat: add Linux UAPI headers formula

torvalds/linux/linux_cmp.gox

@@ -0,0 +1,12 @@
+import "strings"
+
+func linuxVersion(version string) string {
+    // GNU's '~' sorts before the end of a version: v7.2~rc7 < v7.2.
+    version = strings.ReplaceAll(version, "-rc", "~rc")
+    // Keep v5.12-rc1-dontuse below the normal v5.12-rc1 tag.
+    return strings.ReplaceAll(version, "-dontuse", "~dontuse")
+}
+
+compareVer (a, b) => {
+    return gnu.compare(linuxVersion(a.Version), linuxVersion(b.Version))
+}

torvalds/linux/v5.7/linuxHeaders_llar.gox

@@ -0,0 +1,42 @@
+import (
+    "os"
+    "path/filepath"
+)
+
+id "torvalds/linux"
+
+// Linux 5.7 introduced LLVM=1 for both target tools and host Clang.
+fromVer "v5.7"
+
+filter => {
+    return target.require["os"][0] == "linux" &&
+        (target.require["arch"][0] == "amd64" || target.require["arch"][0] == "arm64")
+}
+
+onBuild ctx => {
+    arch := "x86"
+    if target.require["arch"][0] == "arm64" {
+        arch = "arm64"
+    }
+    a := autotools.new(ctx.SourceDir, ctx.SourceDir, ctx.outputDir)
+    a.build "headers_install", "ARCH="+arch, "LLVM=1", "INSTALL_HDR_PATH="+ctx.outputDir+"/usr"
+}
+
+onTest ctx => {
+    triple := "x86_64-linux-gnu"
+    readNumber := "0"
+    if target.require["arch"][0] == "arm64" {
+        triple = "aarch64-linux-gnu"
+        readNumber = "63"
+    }
+    source := filepath.join(ctx.SourceDir, "headers-consumer.c")
+    os.writeFile! source, []byte(`#include <asm/unistd.h>
+#include <linux/futex.h>
+#include <linux/netlink.h>
+_Static_assert(__NR_read == EXPECT_NR_READ, "wrong architecture headers");
+_Static_assert(sizeof(struct nlmsghdr) == 16, "invalid netlink ABI");
+_Static_assert(sizeof(__u64) == 8, "invalid UAPI integer size");
+`), 0o644
+    clang! "--target="+triple, "-fsyntax-only", "-nostdinc",
+        "-I"+filepath.join(ctx.outputDir, "usr", "include"), "-DEXPECT_NR_READ="+readNumber, source
+}

torvalds/linux/versions.json

@@ -0,0 +1,4 @@
+{
+    "path": "torvalds/linux",
+    "deps": {}
+}