Enable buflib and core_alloc for warble.

Most of the work comes from http://gerrit.rockbox.org/r/#/c/1088/
by Thomas Jarosch.

Change-Id: Iaa673dad2388d1e44fc95ffaa14bafadc6158101

lib/rbcodec/rbcodecplatform-unix.h

@@ -64,6 +64,12 @@ off_t filesize(int fd);
                        putc('\n', stderr);           \
                   } while (0)
 #endif
+#ifndef panicf
+#define panicf(...) do { fprintf(stderr, __VA_ARGS__); \
+                         putc('\n', stderr);           \
+                         exit(-1);                     \
+                    } while (0)
+#endif
 #endif
 */