generate_source_tarball.sh: Support using a subdirectory via TO_COMPRESS

Related: RHEL-30937

java-1.8.0-openjdk.spec

@@ -2945,6 +2945,7 @@ cjc.mainProgram(args)
 - Remove obsolete file update_main_sources.sh
 - generate_source_tarball.sh: Handle an existing checkout
 - generate_source_tarball.sh: Sync indentation with java-21-openjdk version
+- generate_source_tarball.sh: Support using a subdirectory via TO_COMPRESS
 - Sync patch set with portable build
 - Related: RHEL-30937
 

scripts/generate_source_tarball.sh

@@ -97,6 +97,8 @@ if [ "$1" = "help" ] ; then
     echo "                 (defaults to PROJECT_NAME-VERSION)"
     echo "REPO_ROOT      - the location of the Git repository to archive"
     echo "                 (defaults to OPENJDK_URL/PROJECT_NAME/REPO_NAME.git)"
+    echo "TO_COMPRESS    - what part of clone to pack"
+    echo "                 (defaults to ${VERSION})"
     echo "JCONSOLE_PATCH - the path to a patch to fix non-availiability of"
     echo "                 jconsole.js (optional; defaults to ${JCONSOLE_PATCH_DEFAULT})"
     echo "BOOT_JDK       - the bootstrap JDK to satisfy the configure run"
@@ -206,6 +208,11 @@ if [ "$REPO_ROOT" = "" ] ; then
     echo "No repository root specified; default to ${REPO_ROOT}"
 fi;
 
+if [ "$TO_COMPRESS" = "" ] ; then
+    TO_COMPRESS="${VERSION}"
+    echo "No targets to be compressed specified ; default to ${TO_COMPRESS}"
+fi;
+
 echo -e "Settings:"
 echo -e "\tVERSION: ${VERSION}"
 echo -e "\tPROJECT_NAME: ${PROJECT_NAME}"
@@ -214,6 +221,7 @@ echo -e "\tOPENJDK_URL: ${OPENJDK_URL}"
 echo -e "\tCOMPRESSION: ${COMPRESSION}"
 echo -e "\tFILE_NAME_ROOT: ${FILE_NAME_ROOT}"
 echo -e "\tREPO_ROOT: ${REPO_ROOT}"
+echo -e "\tTO_COMPRESS: ${TO_COMPRESS}"
 echo -e "\tJCONSOLE_PATCH: ${JCONSOLE_PATCH}"
 echo -e "\tBOOT_JDK: ${BOOT_JDK}"
 
@@ -295,7 +303,7 @@ pushd "${FILE_NAME_ROOT}"
     TARBALL_NAME=${FILE_NAME_ROOT}.tar.${COMPRESSION}
     XZ_OPT=${XZ_OPT-"-T0"} \
           tar --mtime="${TAR_TIME}" --owner=root --group=root --sort=name \
-          --exclude-vcs -$SWITCH "${TARBALL_NAME}" "${VERSION}"
+          --exclude-vcs -$SWITCH "${TARBALL_NAME}" "${TO_COMPRESS}"
     mv "${TARBALL_NAME}" ..
 popd
 if [ "$WITH_TEMP" != "" ] ; then