Fix building when configured with --disable-shared.

The problem was that the function safe_malloc_mul_2op_() was originally
defined as static inline in inclide/share/alloc.h but had to be moved
because GCC was refusing to inline it. Once moved however, static linking
would fail when building the flac executable because the function ended
up beiong linked twice.
diff --git a/src/libFLAC/metadata_object.c b/src/libFLAC/metadata_object.c
index 7f178f8..149f78d 100644
--- a/src/libFLAC/metadata_object.c
+++ b/src/libFLAC/metadata_object.c
@@ -37,10 +37,14 @@
 #include <string.h>
 
 #include "private/metadata.h"
+#include "private/memory.h"
 
 #include "FLAC/assert.h"
 #include "share/alloc.h"
 
+/* Alias the first (in share/alloc.h) to the second (in src/libFLAC/memory.c). */
+#define safe_malloc_mul_2op_ safe_malloc_mul_2op_p
+
 
 /****************************************************************************
  *
@@ -151,7 +155,7 @@
 	else {
 		FLAC__StreamMetadata_CueSheet_Index *x;
 		FLAC__ASSERT(from->num_indices > 0);
-		if(0 == (x = safe_malloc_mul_2op_(from->num_indices, /*times*/sizeof(FLAC__StreamMetadata_CueSheet_Index))))
+		if(0 == (x = safe_malloc_mul_2op_p(from->num_indices, /*times*/sizeof(FLAC__StreamMetadata_CueSheet_Index))))
 			return false;
 		memcpy(x, from->indices, from->num_indices * sizeof(FLAC__StreamMetadata_CueSheet_Index));
 		to->indices = x;
@@ -173,7 +177,7 @@
 
 	FLAC__ASSERT(num_points > 0);
 
-	object_array = safe_malloc_mul_2op_(num_points, /*times*/sizeof(FLAC__StreamMetadata_SeekPoint));
+	object_array = safe_malloc_mul_2op_p(num_points, /*times*/sizeof(FLAC__StreamMetadata_SeekPoint));
 
 	if(0 != object_array) {
 		unsigned i;