deplist.py: support dependency hints.

deplist.config.in

@@ -1,4 +1,3 @@
---inc-oo
 --check-colour yellow
 # Check whether the dependency graph is acyclic:
 --check-cycles

mkhelper.mk.in

@@ -192,8 +192,8 @@ sanitize-mod-proxies:
 # Dependency generation rule for undetectable Fortran dependencies:
 extra_f90.d: mkhelper.mk
 	$(silent_DEPGEN):;{ \
-	  echo 'src/program/main.o:| src/program/implicit_external.o'; \
-	  echo 'src/program/main.o:| src/modules/submo_test_submodule.o'; \
+	  echo '#-hint src/program/main.o: src/program/implicit_external.o'; \
+	  echo '#-hint src/program/main.o: src/modules/submo_test_submodule.o'; \
 	} >$@
 
 # Configure delayed bundled libraries:

mkhelper/deplist.py

@@ -48,10 +48,11 @@
 import sys
 
 _re_rule = re.compile(
+    r"^(?P<hint>#-hint )?"
     # targets
-    r"^[ ]*(?P<targets>[-+\w./]+(?:[ ]+[-+\w./]+)*)[ ]*"
+    r"[ ]*(?P<targets>[-+\w./]+(?:[ ]+[-+\w./]+)*)[ ]*"
     # normal prerequisites
-    r":(?:[ ]*(?P<normal>[-+\w./]+(?:[ ]+[-+\w./]+)*))?[ ]*"
+    r":[ ]*(?P<normal>[-+\w./]+(?:[ ]+[-+\w./]+)*)?[ ]*"
     # order-only prerequisites
     r"(?:\|[ ]*(?P<order_only>[-+\w./]+(?:[ ]+[-+\w./]+)*))?"
 )