unwind: fix build on 32-bit architectures

Fix compilation warnings in unwind.c on 32-bit architectures.
On some architectures getuid is actually getuid32, so change the test
to use getpid instead of getuid.

* unwind.c (STACK_ENTRY_SYMBOL_FMT): Explicitly cast function_off_set
to unsigned long.
(queue_put_error): Change the 3rd argument's type to unsigned long.
* tests/stack-fcall.c (f1): Use getpid instead of getuid.
* tests/strace-k.test: Likewise.
diff --git a/unwind.c b/unwind.c
index 797a287..21f2a48 100644
--- a/unwind.c
+++ b/unwind.c
@@ -403,7 +403,7 @@
 	" > %s(%s+0x%lx) [0x%lx]\n",		\
 	binary_filename,			\
 	symbol_name,				\
-	function_off_set,			\
+	(unsigned long) function_off_set,	\
 	true_offset
 #define STACK_ENTRY_NOSYMBOL_FMT		\
 	" > %s() [0x%lx]\n",			\
@@ -523,7 +523,7 @@
 static void
 queue_put_error(void *queue,
 		const char *error,
-		unw_word_t ip)
+		unsigned long ip)
 {
 	queue_put(queue, NULL, NULL, 0, ip, error);
 }