fix a few CLang warnings

most of them quite insignificant, but still annoying. The only
exception is the warning about the changed alignment for the 'work'
argument of spu_implicit_assemble(). AFAICT, the only reason why it
worked was that the pointer produced by malloc() was passed
directly. (malloc() seems to fulfill all alignment criteria.) To fix
this, I've changed that argument's type from char* to double*.

opm/core/grid/cpgpreprocess/geometry.c

@@ -316,7 +316,7 @@ compute_cell_geometry_3d(double *coords,
 	    }
 
 	    if(subnormal_sign < 0.0){
-		tet_volume =- tet_volume;
+		tet_volume = -tet_volume;
 	    }
 	    if(!(neighbors[2*face+0]==c)){
 		tet_volume = -tet_volume;

opm/core/props/BlackoilPropertiesInterface.hpp

@@ -23,7 +23,7 @@
 namespace Opm
 {
 
-    class PhaseUsage;
+    struct PhaseUsage;
 
     /// Abstract base class for blackoil fluid and reservoir properties.
     /// Supports variable number of spatial dimensions, called D.

opm/core/simulator/SimulatorCompressibleTwophase.cpp

@@ -96,8 +96,8 @@ namespace Opm
         const RockCompressibility* rock_comp_props_;
         WellsManager& wells_manager_;
         const Wells* wells_;
-        const std::vector<double>& src_;
-        const FlowBoundaryConditions* bcs_;
+        //const std::vector<double>& src_;
+        //const FlowBoundaryConditions* bcs_;
         const double* gravity_;
         // Solvers
         CompressibleTpfa psolver_;
@@ -245,8 +245,8 @@ namespace Opm
           rock_comp_props_(rock_comp_props),
           wells_manager_(wells_manager),
           wells_(wells_manager.c_wells()),
-          src_(src),
-          bcs_(bcs),
+          //src_(src),
+          //bcs_(bcs),
           gravity_(gravity),
           psolver_(grid, props, rock_comp_props, linsolver,
                    param.getDefault("nl_pressure_residual_tolerance", 0.0),

opm/core/simulator/SimulatorIncompTwophase.hpp

@@ -118,7 +118,7 @@ namespace Opm
         void connect_timestep (T& t);
 
     private:
-        class Impl;
+        struct Impl;
         // Using shared_ptr instead of scoped_ptr since scoped_ptr requires complete type for Impl.
         boost::shared_ptr<Impl> pimpl_;
 

opm/core/transport/minimal/spu_implicit.c

@@ -139,7 +139,7 @@ spu_implicit(struct UnstructuredGrid *g, double *s0, double *s, double h, double
     double infnorm;
     double *b;
     double *x;
-    char *work;
+    double *work;
     double *mob, *dmob;
     int i;
     int it;
@@ -277,12 +277,12 @@ phase_upwind_mobility(double darcyflux, double gravityflux,  int i, int c,
 void
 spu_implicit_assemble(struct UnstructuredGrid *g, double *s0, double *s, double *mob, double *dmob,
                       double *dflux, double *gflux, double *src, double dt, sparse_t *S,
-                      double *b, char *work)
+                      double *b, double *work)
 {
     int     i, k, f, c1, c2, c;
     int     nc   = g->number_of_cells;
 
-    double *m   = (double*)work;
+    double *m   = (double*) work;
     double *dm  =  m + 2;
     int    *cix = (int*)(dm + 2);
     double  m1,  m2, dm1, dm2, mt2;

opm/core/transport/minimal/spu_implicit.h

@@ -19,7 +19,7 @@ typedef struct Sparse {
 void
 spu_implicit_assemble(struct UnstructuredGrid *g, double *s0, double *s, double *mob, double *dmob,
                       double *dflux, double *gflux, double *src, double dt, sparse_t *S,
-                      double *b, char *work);
+                      double *b, double *work);
 
 double
 spu_implicit(struct UnstructuredGrid *g, double *s0, double *s, double h, double x0, int ntab, double *tab,