rts: Move libdwPrintBacktrace to public interface

Reviewers: erikd, simonmar

Reviewed By: simonmar

Subscribers: rwbarton, thomie

Differential Revision: https://phabricator.haskell.org/D4194

includes/rts/Libdw.h

@@ -8,6 +8,9 @@
 
 #pragma once
 
+// for FILE
+#include <stdio.h>
+
 // Chunk capacity
 // This is rather arbitrary
 #define BACKTRACE_CHUNK_SZ 256
@@ -89,3 +92,6 @@ Backtrace *libdwGetBacktrace(LibdwSession *session);
 /* Lookup Location information for the given address.
  * Returns 0 if successful, 1 if address could not be found. */
 int libdwLookupLocation(LibdwSession *session, Location *loc, StgPtr pc);
+
+/* Pretty-print a backtrace to the given FILE */
+void libdwPrintBacktrace(LibdwSession *session, FILE *file, Backtrace *bt);

rts/Libdw.h

@@ -23,9 +23,6 @@ LibdwSession *libdwInit(void);
 /* Free a session */
 void libdwFree(LibdwSession *session);
 
-/* Pretty-print a backtrace to std*/
-void libdwPrintBacktrace(LibdwSession *session, FILE *file, Backtrace *bt);
-
 // Traverse backtrace in order of outer-most to inner-most frame
 #define FOREACH_FRAME_INWARDS(pc, bt)                                 \
     BacktraceChunk *_chunk;                                           \