[build] Replace '$zx' with '//zircon'

Also replace '//zircon/public/lib/{bitmap,fbl,zircon-internal}'
with the corresponding '//zircon/system/ulib/' target, since the
former are simple redirection groups that were used during build
unification.

Bug: 61979
Change-Id: I9b7001dafdbae1d6fa64aa58d8b48b2976d09977
diff --git a/BUILD.gn b/BUILD.gn
index 1c90866..aa1bb00 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -27,7 +27,7 @@
 
 # Disable warnings we won't fix in third-party code.  Putting this in a
 # separate config rather than directly in the target gets these flags
-# correctly ordered after the $zx/public/gn/config:default_warnings flags.
+# correctly ordered after the //build/config:default_warnings flags.
 config("disable_warnings") {
   visibility = [ ":*" ]
 
@@ -50,6 +50,7 @@
     # TODO(41663): UBSan has found an instance of undefined behavior in this target.
     # Disable UBSan for this target temporarily until it is migrated into CI/CQ.
     "//build/config:temporarily_disable_ubsan_do_not_use",
+
     # TODO(fxb/58162): delete the below and fix compiler warnings
     "//build/config:Wno-conversion",
   ]
@@ -63,7 +64,7 @@
   cflags = [ "-fno-strict-aliasing" ]
 
   sources = [
-    "$zx/system/ulib/acpica/osfuchsia.cc",
+    "//zircon/system/ulib/acpica/osfuchsia.cc",
     "source/common/ahids.c",
     "source/common/ahpredef.c",
     "source/common/ahtable.c",
@@ -240,9 +241,9 @@
   deps = [
     "//src/devices/pci/lib/pci",
     "//src/lib/ddk",
-    "//zircon/public/lib/fbl",
-    "//zircon/public/lib/zircon-internal",
-    "//zircon/public/lib/bitmap",
+    "//zircon/system/ulib/bitmap",
+    "//zircon/system/ulib/fbl",
+    "//zircon/system/ulib/zircon-internal",
   ]
   defines = [ "_ALL_SOURCE" ]
   if (acpica_debug_output) {