Description: only replace the generated source when they differ.
 Passing -m to gprbuild already avoids unnecessary recompilations,
 but does not allow deterministic timestamps in ALI files.
Author: Nicolas Boulenguez <nicolas@debian.org>

--- a/Makefile
+++ b/Makefile
@@ -48,6 +48,9 @@
 generate_sources:
 	-if [ -f src/obj/gnatcoll_db2ada${EXE} ]; then \
 	   echo "Regenerating files in src/generated/."; \
+	   for f in src/generated/*.ad?; do \
+	      mv $$f $$f.old; \
+	   done; \
 	   src/obj/gnatcoll_db2ada${EXE} -dbtype=sqlite -dbname=:memory: \
 		-output src/generated \
 		-dbmodel=src/dbschema.txt \
@@ -59,6 +62,11 @@
 		-enum "e2e_kind,id,name,E2E_,Integer"; \
 	   for f in src/generated/*.ad?; do \
 	      tr -d '\r' < $$f > $$f.tmp && mv $$f.tmp $$f; \
+	      if diff -q $$f.old $$f ; then \
+	         mv $$f.old $$f; \
+	      else \
+	         rm $$f.old; \
+	      fi; \
 	   done; \
 	fi