liblzma: Fix compilation of price_tablegen.c.

It is built and run only manually so this didn't matter
unless one wanted to regenerate the price_table.c.

(cherry picked from commit 8e4ec794836bc1701d8c9bd5e347b8ce8cc5bbb4)

src/liblzma/rangecoder/price_tablegen.c

@@ -15,6 +15,11 @@
 
 #include <inttypes.h>
 #include <stdio.h>
+
+// Make it compile without common.h.
+#define BUILDING_PRICE_TABLEGEN
+#define lzma_attr_visibility_hidden
+
 #include "range_common.h"
 #include "price.h"
 

src/liblzma/rangecoder/range_common.h

@@ -14,7 +14,10 @@
 #ifndef LZMA_RANGE_COMMON_H
 #define LZMA_RANGE_COMMON_H
 
-#include "common.h"
+// Skip common.h if building price_tablegen.c.
+#ifndef BUILDING_PRICE_TABLEGEN
+#	include "common.h"
+#endif
 
 
 ///////////////