[PATCH] fix build without sfsexp

[michaeljgruber+grubix+git@gmail.com]

From: Michael J Gruber <git@grubix.eu>

a1d139de ("lib: add sexp: prefix to Xapian (infix) query parser.",
2022-04-09) introduced sfsexp infix queries. This requires the infix
preprocessor to be built in in a way which does not require sfsexp when
notmuch is built without it.

Make the preprocessor throw a Xapian error in this case (and fix the
build).

Signed-off-by: Michael J Gruber <git@grubix.eu>
---
Maybe something like this - I have not test *with* sfsexp, though.

 lib/database-private.h | 4 ----
 lib/query.cc           | 2 ++
 lib/sexp-fp.cc         | 4 ++++
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/lib/database-private.h b/lib/database-private.h
index 657b1aa1..419b9fe6 100644
--- a/lib/database-private.h
+++ b/lib/database-private.h
@@ -354,10 +354,6 @@ _notmuch_query_string_to_xapian_query (notmuch_database_t *notmuch,
 				       std::string query_string,
 				       Xapian::Query &output,
 				       std::string &msg);
-/* parse-sexp.cc */
-notmuch_status_t
-_notmuch_sexp_string_to_xapian_query (notmuch_database_t *notmuch, const char *querystr,
-				      Xapian::Query &output);
 
 notmuch_status_t
 _notmuch_query_expand (notmuch_database_t *notmuch, const char *field, Xapian::Query subquery,
diff --git a/lib/query.cc b/lib/query.cc
index b0937fcc..707f6222 100644
--- a/lib/query.cc
+++ b/lib/query.cc
@@ -227,6 +227,7 @@ _notmuch_query_ensure_parsed_xapian (notmuch_query_t *query)
     return NOTMUCH_STATUS_SUCCESS;
 }
 
+#if HAVE_SFSEXP
 static notmuch_status_t
 _notmuch_query_ensure_parsed_sexpr (notmuch_query_t *query)
 {
@@ -243,6 +244,7 @@ _notmuch_query_ensure_parsed_sexpr (notmuch_query_t *query)
     _notmuch_query_cache_terms (query);
     return NOTMUCH_STATUS_SUCCESS;
 }
+#endif
 
 static notmuch_status_t
 _notmuch_query_ensure_parsed (notmuch_query_t *query)
diff --git a/lib/sexp-fp.cc b/lib/sexp-fp.cc
index ed26f6ec..1fdf5225 100644
--- a/lib/sexp-fp.cc
+++ b/lib/sexp-fp.cc
@@ -30,10 +30,14 @@ SexpFieldProcessor::operator() (const std::string & query_string)
     notmuch_status_t status;
     Xapian::Query output;
 
+#if HAVE_SFSEXP
     status = _notmuch_sexp_string_to_xapian_query (notmuch, query_string.c_str (), output);
     if (status) {
 	throw Xapian::QueryParserError ("error parsing " + query_string);
     }
+#else
+    throw Xapian::QueryParserError ("sexp query parser not available");
+#endif
 
     return output;
 
-- 
2.36.0.rc2.472.gf6a51f5f41