kernel_headers: kernel headers library package

This change is foundational for converting many modules that
depend on kernel headers built via the platform build system.

Bug: 143567008
Change-Id: I5808a8464ed30287b75baac9a74285bff5825fe2
[[email protected]: add logic to iterate over mandatory headers
 and only generate these headers if not already present in
 usr/include/asm.]
Signed-off-by: Rishabh Bhatnagar <[email protected]>
Signed-off-by: Prateek Sood <[email protected]>

Android.bp

@@ -3,25 +3,43 @@ cc_binary_host {
     srcs: ["scripts/unifdef.c"],
     sanitize: {
         never: true,
-    }
+    },
 }
 
-gensrcs {
-    name: "qseecom-kernel-includes",
-
-    // move to out/ as root for header generation because of scripts/unifdef
-    // storage - at the expense of extra ../ references
-    cmd: "pushd out && mkdir -p scripts && rm -f scripts/unifdef && ln -s ../../$(location unifdef) scripts/unifdef && ../$(location scripts/headers_install.sh) `dirname ../$(out)` ../ $(in) && popd",
-
+genrule {
+    name: "gen-headers_install.sh",
+    srcs: ["scripts/headers_install.sh"],
     tools: ["unifdef"],
-    tool_files: ["scripts/headers_install.sh"],
-    export_include_dirs: ["include/uapi"],
-    srcs: ["include/uapi/linux/qseecom.h"],
-    output_extension: "h",
+    out: ["headers_install.sh"],
+    cmd: "sed 's+scripts/unifdef+$(location unifdef)+g' $(in) > $(out)",
+}
+
+cc_prebuilt_binary {
+    name: "headers_install.sh",
+    device_supported: false,
+    host_supported: true,
+    srcs: [":gen-headers_install.sh"],
 }
 
+// Use the following for verbose output from kernel_headers.py.
+// kernel_headers_verbose = "--verbose "
+// Use the following for minimal output from kernel_headers.py.
+kernel_headers_verbose = ""
+
+build = ["gen_headers_arm.bp", "gen_headers_arm64.bp"]
+
 cc_library_headers {
-    name: "qseecom-kernel-headers",
-    generated_headers: ["qseecom-kernel-includes"],
-    export_generated_headers: ["qseecom-kernel-includes"],
+    name: "qti_kernel_headers",
+    arch: {
+        arm: {
+            generated_headers: ["qti_generate_kernel_headers_arm"],
+            export_generated_headers: ["qti_generate_kernel_headers_arm"],
+        },
+        arm64: {
+            generated_headers: ["qti_generate_kernel_headers_arm64"],
+            export_generated_headers: ["qti_generate_kernel_headers_arm64"],
+        },
+    },
+    vendor: true,
+    recovery_available: true,
 }