disable ASDLGEN if hg won't work, or if python is not installed.
This change makes configure check for
- the existence of a hg repository
- the hg executable itself
- the python executable
Running $(srcdir)/Parser/asdl_c.py (i.e. ASDLGEN) will fail if any of
the above prerequisites is missing, so we now disable it instead.
closes #12225
diff --git a/Makefile.pre.in b/Makefile.pre.in
index b93e482..694faad 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -274,7 +274,7 @@
ASDLGEN_FILES= $(srcdir)/Parser/asdl.py $(srcdir)/Parser/asdl_c.py
# XXX Note that a build now requires Python exist before the build starts
-ASDLGEN= $(srcdir)/Parser/asdl_c.py
+ASDLGEN= @DISABLE_ASDLGEN@ $(srcdir)/Parser/asdl_c.py
##########################################################################
# Python