kernel: Create and export kernel headers

Create a header library which export kernel headers.
These headers are needed by modules and userspace libraries.
This is snapshot merge from msm-5.10 branch commit 1c21e750af93 ("Merge
"drivers: dcvs: memlat: add scheme for adaptive boosting"").

Change-Id: If685678193e829a367ed672e0de345262235a2d5
Signed-off-by: Mulugeta Engdaw <mengdaw@codeaurora.org>
Signed-off-by: Jeevan Shriram <jshriram@codeaurora.org>

Android.bp

@@ -0,0 +1,21 @@
+cc_binary_host {
+    name: "unifdef",
+    srcs: ["scripts/unifdef.c"],
+    sanitize: {
+        never: true,
+    },
+}
+
+genrule {
+    name: "gen-headers_install.sh",
+    srcs: ["scripts/headers_install.sh"],
+    tools: ["unifdef"],
+    out: ["headers_install.sh"],
+    cmd: "sed 's+scripts/unifdef+$${LOC_UNIFDEF:-$$(dirname $$0)/unifdef}+g' $(in) > $(out)",
+}
+
+sh_binary_host {
+    name: "headers_install.sh",
+    src: ":gen-headers_install.sh",
+    required: ["unifdef"],
+}