fix aligned_alloc on windows

Another attempt at #24 (closed). Follow-up to !214 (merged).

pystencils/backends/cbackend.py

@@ -282,13 +282,14 @@ class CBackend:
         np_dtype = node.symbol.dtype.base_type.numpy_dtype
         required_size = np_dtype.itemsize * node.size + align
         size = modulo_ceil(required_size, align)
-        code = "#if __cplusplus >= 201703L\n"
+        code = "#if __cplusplus >= 201703L || __STDC_VERSION__ >= 201112L\n"
         code += "{dtype} {name}=({dtype})aligned_alloc({align}, {size}) + {offset};\n"
         code += "#elif defined(_MSC_VER)\n"
         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});\n"
+        code += "{name} += {offset};\n"
         code += "#endif"
         return code.format(dtype=node.symbol.dtype,
                            name=self.sympy_printer.doprint(node.symbol.name),