Add API to set page size compat mode

Adding APIs in libdl to set linker global which will be used to set the page size compat mode for particular app.

Test: atest bionic-unit-tests
Test: atest CtsBionicTestCases
Bug: 371049373

Change-Id: I20f0fe9ece5db833568edf27ec268edf999f1741
diff --git a/libdl/libdl_android.map.txt b/libdl/libdl_android.map.txt
index 7afcd9c..efbc841 100644
--- a/libdl/libdl_android.map.txt
+++ b/libdl/libdl_android.map.txt
@@ -24,6 +24,7 @@
     android_init_anonymous_namespace; # apex
     android_link_namespaces; # apex
     android_set_application_target_sdk_version; # apex
+    android_set_16kb_appcompat_mode; #apex
   local:
     *;
 };