Unwind: use arch generic assignment

The unw_proc_info_t member unwind_info might be of different type
depending on the architecture.

    ../../CRT.c: In function ‘print_backtrace’:
    ../../CRT.c:1099:23: error: assignment to ‘unw_word_t’ {aka ‘long unsigned int’} from ‘void *’ makes integer from pointer without a cast [-Werror=int-conversion]
     1099 |       pip.unwind_info = NULL;
          |                       ^

1 files changed, 1 insertions, 1 deletions

diff --git a/CRT.c b/CRT.c
index 632548a4..64c259fc 100644
--- a/CRT.c
+++ b/CRT.c
@@ -1096,7 +1096,7 @@ static void print_backtrace(void) {
       unw_get_proc_name(&cursor, symbolName, sizeof(symbolName), &offset);
 
       unw_proc_info_t pip;
-      pip.unwind_info = NULL;
+      pip.unwind_info = 0;
 
       const char* fname = "?";
       const void* ptr = 0;