diff --git a/sql/Makefile b/sql/Makefile
index 42bdeeb7..19cfb435 100644
--- a/sql/Makefile
+++ b/sql/Makefile
@@ -1,78 +1,78 @@
 # Depends: postgresql-client, postgresql-autodoc
 
 DBNAME = softwareheritage-dev
 DOCDIR = autodoc
 
 SQL_INIT    = 10-swh-init.sql
 SQL_ENUMS   = 20-swh-enums.sql
 SQL_SCHEMA  = 30-swh-schema.sql
 SQL_FUNC    = 40-swh-func.sql
 SQL_INDEX   = 60-swh-indexes.sql
 SQL_TRIGGER = 70-swh-triggers.sql
 SQLS = $(SQL_INIT) $(SQL_ENUMS) $(SQL_SCHEMA) $(SQL_FUNC) $(SQL_INDEX) $(SQL_TRIGGER)
 SQL_FILES = $(abspath $(addprefix $(CURDIR)/../swh/storage/sql/,$(SQLS)))
 
 PSQL_BIN = psql
 PSQL_FLAGS = --echo-errors -X -v ON_ERROR_STOP=1
 PSQL = $(PSQL_BIN) $(PSQL_FLAGS)
 
 PIFPAF=$(findstring postgresql://,$(PIFPAF_URLS))
 
 all:
 
 createdb: createdb-stamp
 createdb-stamp: $(SQL_FILES)
-ifndef PIFPAF
+ifeq ($(PIFPAF),)
 	-dropdb $(DBNAME)
 endif
 	createdb $(DBNAME)
-ifndef PIFPAF
+ifeq ($(PIFPAF),)
 	touch $@
 else
 	rm -f $@
 endif
 
 filldb: filldb-stamp
 filldb-stamp: createdb-stamp
 	cat $(SQL_FILES) | $(PSQL) $(DBNAME)
-ifndef PIFPAF
+ifeq ($(PIFPAF),)
 	touch $@
 else
 	rm -f $@
 endif
 
 dropdb:
 	-dropdb $(DBNAME)
 
 dumpdb: swh.dump
 swh.dump: filldb-stamp
 	pg_dump -Fc $(DBNAME) > $@
 
 $(DOCDIR):
 	test -d $(DOCDIR)/ || mkdir $(DOCDIR)
 
 doc: autodoc-stamp $(DOCDIR)/db-schema.pdf $(DOCDIR)/db-schema.svg
 autodoc-stamp: filldb-stamp $(DOCDIR)
 	postgresql_autodoc -d $(DBNAME) -f $(DOCDIR)/db-schema
 	cp -a $(DOCDIR)/db-schema.dot $(DOCDIR)/db-schema.dot.orig
-ifndef PIFPAF
+ifeq ($(PIFPAF),)
 	touch $@
 else
 	rm -f $@
 endif
 
 $(DOCDIR)/db-schema.dot: clusters.dot autodoc-stamp $(DOCDIR)
 	bin/dot_add_content $(DOCDIR)/db-schema.dot.orig clusters.dot > $(DOCDIR)/db-schema.dot
 
 $(DOCDIR)/db-schema.pdf: $(DOCDIR)/db-schema.dot autodoc-stamp
 	dot -T pdf $< > $@
 $(DOCDIR)/db-schema.svg: $(DOCDIR)/db-schema.dot autodoc-stamp
 	dot -T svg $< > $@
 
 clean:
 	rm -rf *-stamp $(DOCDIR)/
 
 distclean: clean dropdb
 	rm -f swh.dump
 
 .PHONY: all initdb createdb dropdb doc clean