Add support for AArch64 XOM binaries.

Adds build system support for generating AArch64 binaries with
execute-only memory layouts via a new xom module property. Also adds
support for an ENABLE_XOM build flag for global builds.

Bug: 77958880
Test: make -j ENABLE_XOM=true
Change-Id: Ia2ea981498dd12941aaf5ca807648ae37527e3ee
diff --git a/android/variable.go b/android/variable.go
index fbbde36..0b344f9 100644
--- a/android/variable.go
+++ b/android/variable.go
@@ -211,6 +211,9 @@
 	CFIExcludePaths *[]string `json:",omitempty"`
 	CFIIncludePaths *[]string `json:",omitempty"`
 
+	EnableXOM       *bool     `json:",omitempty"`
+	XOMExcludePaths *[]string `json:",omitempty"`
+
 	VendorPath          *string `json:",omitempty"`
 	OdmPath             *string `json:",omitempty"`
 	ProductPath         *string `json:",omitempty"`