Fix failures caused by lack of ANDROID_BUILD_TOP on build servers

Bug: 226686554
Bug: 218685706
Test: unset ANDROID_BUILD_TOP
      packages/modules/common/build/mainline_modules_sdks.sh
Change-Id: I1da4309e0537b251b3f7a6c2160bef77e6f218ff
diff --git a/build/mainline_modules_sdks.sh b/build/mainline_modules_sdks.sh
index 766bafc..35a677e 100755
--- a/build/mainline_modules_sdks.sh
+++ b/build/mainline_modules_sdks.sh
@@ -56,6 +56,10 @@
   # provided by the build to ensure consistency across build environments.
   export DIST_DIR OUT_DIR
 
+  # Make sure that the ANDROID_BUILD_TOP (which is the same as the current
+  # directory as checked above) is exported to Python.
+  export ANDROID_BUILD_TOP="${PWD}"
+
   # The path to this tool is the .sh script that lives alongside the .py script.
   TOOL_PATH="${py3script%.py}.sh"
   prebuilts/build-tools/linux-x86/bin/py3-cmd -u "${py3script}" \