fix usage of posix_memalign

pystencils/backends/cbackend.py

@@ -288,7 +288,7 @@ class CBackend:
         code += "{dtype} {name}=({dtype})_aligned_malloc({size}, {align}) + {offset};\n"
         code += "#else\n"
         code += "{dtype} {name};\n"
-        code += "posix_memalign(&{name}, {align}, {size}) + {offset};\n"
+        code += "posix_memalign((void**) &{name}, {align}, {size}) + {offset};\n"
         code += "#endif"
         return code.format(dtype=node.symbol.dtype,
                            name=self.sympy_printer.doprint(node.symbol.name),