Change default for source_build config variable to true.

To reflect the new (temporary) true default in make.

Test: m
Bug: 172480615
Change-Id: I9a32578554650776c1d6b3920fa233c5613a05e3

scripts/build-aml-prebuilts.sh

@@ -77,6 +77,9 @@ readonly SOONG_VARS=${SOONG_OUT}/soong.variables
 # CrossHost: linux_bionic
 # CrossHostArch: x86_64
 #   -  Enable Bionic on host as ART needs prebuilts for it.
+# VendorVars.art_mdoule.source_build
+#   -  TODO(b/172480615): Change default to false when platform uses ART Module
+#      prebuilts by default.
 cat > ${SOONG_VARS}.new << EOF
 {
     "BuildNumberFile": "build_number.txt",
@@ -98,7 +101,7 @@ cat > ${SOONG_VARS}.new << EOF
 
     "VendorVars": {
         "art_module": {
-            "source_build": "${ENABLE_ART_SOURCE_BUILD:-false}"
+            "source_build": "${ENABLE_ART_SOURCE_BUILD:-true}"
         }
     }
 }