src/libFLAC/include/private/macros.h : Fix flac_min.

The existing flac_min macro was generating -Wshadow compiler warnings
when nested.

src/libFLAC/include/private/macros.h

@@ -39,10 +39,14 @@
     __typeof__ (b) _b = (b); \
     _a > _b ? _a : _b; })
 
-#define flac_min(a,b) \
-    ({ __typeof__ (a) _a = (a); \
-    __typeof__ (b) _b = (b); \
-    _a < _b ? _a : _b; })
+#define MIN_PASTE(A,B) A##B
+#define MIN_IMPL(A,B,L) ({ \
+    __typeof__(A) MIN_PASTE(__a,L) = (A); \
+    __typeof__(B) MIN_PASTE(__b,L) = (B); \
+    MIN_PASTE(__a,L) < MIN_PASTE(__b,L) ? MIN_PASTE(__a,L) : MIN_PASTE(__b,L); \
+    })
+
+#define flac_min(A,B) MIN_IMPL(A,B,__COUNTER__)
 
 /* Whatever other unix that has sys/param.h */
 #elif defined(HAVE_SYS_PARAM_H)