Use __cdecl also for function pointers in liblzma API when

on Windows.

src/liblzma/api/lzma.h

@@ -154,15 +154,19 @@
  ******************/
 
 /*
- * Some systems require that the functions are declared specially
- * in the headers.
+ * Some systems require (or at least recommend) that the functions and
+ * function pointers are declared specially in the headers.
  */
+#ifdef _WIN32
+#	define LZMA_API_CALL __cdecl
+#	define LZMA_API_IMPORT __declspec(dllimport)
+#else
+#	define LZMA_API_CALL
+#	define LZMA_API_IMPORT
+#endif
+
 #ifndef LZMA_API
-#	if defined(_WIN32)
-#		define LZMA_API __cdecl __declspec(dllimport)
-#	else
-#		define LZMA_API
-#	endif
+#	define LZMA_API LZMA_API_CALL LZMA_API_IMPORT
 #endif
 
 

src/liblzma/api/lzma/base.h

@@ -376,7 +376,7 @@ typedef struct {
 	 *              returned NULL if some function from liblzma
 	 *              returns LZMA_MEM_ERROR.
 	 */
-	void *(*alloc)(void *opaque, size_t nmemb, size_t size);
+	void *(LZMA_API_CALL *alloc)(void *opaque, size_t nmemb, size_t size);
 
 	/**
 	 * \brief       Pointer to a custom memory freeing function
@@ -390,7 +390,7 @@ typedef struct {
 	 *                      or when it is set to NULL, a pointer returned
 	 *                      by the standard malloc().
 	 */
-	void (*free)(void *opaque, void *ptr);
+	void (LZMA_API_CALL *free)(void *opaque, void *ptr);
 
 	/**
 	 * \brief       Pointer passed to .alloc() and .free()

src/liblzma/common/common.h

@@ -24,20 +24,16 @@
 #include "../../common/mythread.h"
 #include "../../common/integer.h"
 
-// Don't use ifdef...
-#if HAVE_VISIBILITY
-#	define LZMA_VISIBILITY __attribute__((__visibility__("default")))
+#if defined(_WIN32)
+#	define LZMA_API_EXPORT __declspec(dllexport)
+// Don't use ifdef or defined() below.
+#elif HAVE_VISIBILITY
+#	define LZMA_API_EXPORT __attribute__((__visibility__("default")))
 #else
-#	define LZMA_VISIBILITY
+#	define LZMA_API_EXPORT
 #endif
 
-#ifdef _WIN32
-#	define LZMA_EXPORT __cdecl __declspec(dllexport)
-#else
-#	define LZMA_EXPORT
-#endif
-
-#define LZMA_API LZMA_VISIBILITY LZMA_EXPORT
+#define LZMA_API LZMA_API_CALL LZMA_API_EXPORT
 
 #include "lzma.h"