display: get unifdef explicitly

Change-Id: Iab81cd0ed9791e7426719fbc1b43d9ccafc89bb7
Signed-off-by: Naseer Ahmed <naseer@codeaurora.org>

Android.bp

@@ -13,7 +13,10 @@ display_headers_out = [
 display_kernel_headers_verbose = "--verbose "
 genrule {
     name: "qti_generate_display_kernel_headers",
-    tools: ["headers_install.sh"],
+    tools: [
+        "headers_install.sh",
+        "unifdef"
+    ],
     tool_files: [
         "display_kernel_headers.py",
     ],
@@ -23,6 +26,7 @@ genrule {
          "--header_arch arm64 " +
          "--gen_dir $(genDir) " +
          "--display_include_uapi $(locations include/uapi/*/**/*.h) " +
+         "--unifdef $(location unifdef) " +
          "--headers_install $(location headers_install.sh)",
     out: display_headers_out,
 }