[zbi-bootfs] Add SDK flags to allow zbi-bootfs outside of zircon.

Adds SDK and headers to zbi-bootfs and dependents so targets outside of
zircon can depend on zbi-bootfs.

Test: Depend on //zircon/public/lib/zbi-bootfs
PKG-642 #comment

Change-Id: I623886c20998529c121c7d649008446114b179f2
diff --git a/zircon/system/ulib/bootdata/BUILD.gn b/zircon/system/ulib/bootdata/BUILD.gn
index 961eb31..72fbb6f 100644
--- a/zircon/system/ulib/bootdata/BUILD.gn
+++ b/zircon/system/ulib/bootdata/BUILD.gn
@@ -3,6 +3,9 @@
 # found in the LICENSE file.
 
 library("bootdata") {
+  sdk = "source"
+  sdk_headers = [ "bootdata/decompress.h" ]
+
   sources = [
     "decompress.c",
   ]
diff --git a/zircon/system/ulib/bootfs/BUILD.gn b/zircon/system/ulib/bootfs/BUILD.gn
index da7fe3f..a22e7a7 100644
--- a/zircon/system/ulib/bootfs/BUILD.gn
+++ b/zircon/system/ulib/bootfs/BUILD.gn
@@ -3,6 +3,9 @@
 # found in the LICENSE file.
 
 library("bootfs") {
+  sdk = "source"
+  sdk_headers = [ "lib/bootfs/parser.h" ]
+
   sources = [
     "parser.cpp",
   ]
diff --git a/zircon/third_party/ulib/BUILD.gn b/zircon/third_party/ulib/BUILD.gn
index 30dd9055..76bafc5 100644
--- a/zircon/third_party/ulib/BUILD.gn
+++ b/zircon/third_party/ulib/BUILD.gn
@@ -7,6 +7,7 @@
   # listed here.  That is, library() targets with `sdk` set.
   deps = [
     "backtrace",
+    "lz4",
     "ngunwind",
     "safemath",
   ]
diff --git a/zircon/third_party/ulib/lz4/BUILD.gn b/zircon/third_party/ulib/lz4/BUILD.gn
index a629251..e85203e 100644
--- a/zircon/third_party/ulib/lz4/BUILD.gn
+++ b/zircon/third_party/ulib/lz4/BUILD.gn
@@ -3,6 +3,15 @@
 # found in the LICENSE file.
 
 library("lz4") {
+  sdk = "static"
+  sdk_headers = [
+    "lz4/lz4.h",
+    "lz4/lz4frame_static.h",
+    "lz4/lz4frame.h",
+    "lz4/lz4hc.h",
+    "lz4/xxhash.h",
+  ]
+
   host = true
   sources = [
     "lz4.c",