[PATCH] selftests/bpf: Fix conflicts with built-in functions in bpf_iter_ksym

[James Hilliard <james.hilliard1@gmail.com>]

Both tolower and toupper are built in c functions, we should not
redefine them as this can result in a build error.

Fixes the following errors:
progs/bpf_iter_ksym.c:10:20: error: conflicting types for built-in function 'tolower'; expected 'int(int)' [-Werror=builtin-declaration-mismatch]
   10 | static inline char tolower(char c)
      |                    ^~~~~~~
progs/bpf_iter_ksym.c:5:1: note: 'tolower' is declared in header '<ctype.h>'
    4 | #include <bpf/bpf_helpers.h>
  +++ |+#include <ctype.h>
    5 |
progs/bpf_iter_ksym.c:17:20: error: conflicting types for built-in function 'toupper'; expected 'int(int)' [-Werror=builtin-declaration-mismatch]
   17 | static inline char toupper(char c)
      |                    ^~~~~~~
progs/bpf_iter_ksym.c:17:20: note: 'toupper' is declared in header '<ctype.h>'

Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
---
 tools/testing/selftests/bpf/progs/bpf_iter_ksym.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_ksym.c b/tools/testing/selftests/bpf/progs/bpf_iter_ksym.c
index 285c008cbf9c..9ba14c37bbcc 100644
--- a/tools/testing/selftests/bpf/progs/bpf_iter_ksym.c
+++ b/tools/testing/selftests/bpf/progs/bpf_iter_ksym.c
@@ -7,14 +7,14 @@ char _license[] SEC("license") = "GPL";
 
 unsigned long last_sym_value = 0;
 
-static inline char tolower(char c)
+static inline char to_lower(char c)
 {
 	if (c >= 'A' && c <= 'Z')
 		c += ('a' - 'A');
 	return c;
 }
 
-static inline char toupper(char c)
+static inline char to_upper(char c)
 {
 	if (c >= 'a' && c <= 'z')
 		c -= ('a' - 'A');
@@ -54,7 +54,7 @@ int dump_ksym(struct bpf_iter__ksym *ctx)
 	type = iter->type;
 
 	if (iter->module_name[0]) {
-		type = iter->exported ? toupper(type) : tolower(type);
+		type = iter->exported ? to_upper(type) : to_lower(type);
 		BPF_SEQ_PRINTF(seq, "0x%llx %c %s [ %s ] ",
 			       value, type, iter->name, iter->module_name);
 	} else {
-- 
2.34.1