Track dependencies for built SAT solver objects

The difference can be observed by running, e.g.,
touch minisat-2.2.1/minisat/mtl/Sort.h
which now does trigger the required rebuilds.

Author: tautschnig

src/solvers/Makefile

@@ -11,15 +11,15 @@ ifneq ($(MINISAT),)
   MINISAT_INCLUDE=-I $(MINISAT)
   MINISAT_LIB=$(MINISAT)/Solver$(OBJEXT) $(MINISAT)/Proof$(OBJEXT) $(MINISAT)/File$(OBJEXT)
   CP_CXXFLAGS += -DHAVE_MINISAT
-  CLEANFILES += $(MINISAT_LIB) $(patsubst %$(OBJEXT), %.d, $(MINISAT_LIB))
+  CLEANFILES += $(MINISAT_LIB) $(patsubst %$(OBJEXT), %$(DEPEXT), $(MINISAT_LIB))
 endif
 
 ifneq ($(MINISAT2),)
   MINISAT2_SRC=sat/satcheck_minisat2.cpp
   MINISAT2_INCLUDE=-I $(MINISAT2)
   MINISAT2_LIB=$(MINISAT2)/minisat/simp/SimpSolver$(OBJEXT) $(MINISAT2)/minisat/core/Solver$(OBJEXT)
   CP_CXXFLAGS += -DHAVE_MINISAT2 -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS
-  CLEANFILES += $(MINISAT2_LIB) $(patsubst %$(OBJEXT), %.d, $(MINISAT2_LIB))
+  CLEANFILES += $(MINISAT2_LIB) $(patsubst %$(OBJEXT), %$(DEPEXT), $(MINISAT2_LIB))
 endif
 
 ifneq ($(IPASIR),)
@@ -35,7 +35,7 @@ ifneq ($(GLUCOSE),)
   GLUCOSE_INCLUDE=-I $(GLUCOSE)
   GLUCOSE_LIB=$(GLUCOSE)/simp/SimpSolver$(OBJEXT) $(GLUCOSE)/core/Solver$(OBJEXT)
   CP_CXXFLAGS += -DHAVE_GLUCOSE -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS
-  CLEANFILES += $(GLUCOSE_LIB) $(patsubst %$(OBJEXT), %.d, $(GLUCOSE_LIB))
+  CLEANFILES += $(GLUCOSE_LIB) $(patsubst %$(OBJEXT), %$(DEPEXT), $(GLUCOSE_LIB))
 endif
 
 ifneq ($(SQUOLEM2),)
@@ -215,6 +215,11 @@ SOLVER_LIB = $(CHAFF_LIB) $(BOOLEFORCE_LIB) $(MINISAT_LIB) \
         $(MINISAT2_LIB) $(SQUOLEM2_LIB) $(CUDD_LIB) \
         $(PICOSAT_LIB) $(LINGELING_LIB) $(GLUCOSE_LIB) $(CADICAL_LIB)
 
+SOLVER_OBJS = $(filter %$(OBJEXT), $(SOLVER_LIB))
+ifneq ($(SOLVER_OBJS),)
+-include $(SOLVER_OBJS:$(OBJEXT)=$(DEPEXT))
+endif
+
 ###############################################################################
 
 solvers$(LIBEXT): $(OBJ) $(SOLVER_LIB)