Index: /issm/trunk-jpl/externalpackages/petsc/install-3.14-mac-static.sh
===================================================================
--- /issm/trunk-jpl/externalpackages/petsc/install-3.14-mac-static.sh	(revision 27556)
+++ /issm/trunk-jpl/externalpackages/petsc/install-3.14-mac-static.sh	(revision 27557)
@@ -23,4 +23,10 @@
 mv petsc-${VER}/* ${PETSC_DIR}
 rm -rf petsc-${VER}
+
+# Modify source so that Python 3 can be used to compile PETSc
+sed -i'' 's|#!/usr/bin/env python|#!/usr/bin/env python3|g' ${PETSC_DIR}/config/configure.py
+
+# Modify source so that Python >= 3.9 can be used to compile PETSc
+sed -i'' 's|thread.isAlive|thread.is_alive|g' ${PETSC_DIR}/config/BuildSystem/script.py
 
 # Configure