tests/sys/snprintf: use printf_long_long

This is required to support printing 64 bit numbers, as is done in the
test.

In addition that 64 bit formatting test is feature gated, so that users
can simply comment out the `USEMODULE += printf_long_long` to fit tiny
boards.

Co-authored-by: mguetschow <[email protected]>

Author: maribu

tests/sys/snprintf/Makefile

@@ -4,4 +4,9 @@ include ../Makefile.sys_common
 # to compile due to PRI*64 macros not being defined
 FEATURES_BLACKLIST := arch_avr8
 
+# This enables support for printing 64 bit numbers. You can comment this out
+# to shrink the test app. The test will skip the corresponding test
+# automatically if printf_long_long is not used.
+USEMODULE += printf_long_long
+
 include $(RIOTBASE)/Makefile.include

tests/sys/snprintf/main.c

@@ -27,6 +27,8 @@
 #include <string.h>
 #include <unistd.h>
 
+#include "modules.h"
+
 static bool failed = false;
 
 static void check(const char *expected, const char *got, int retval)
@@ -277,7 +279,12 @@ int main(void)
     test_int8();
     test_int16();
     test_int32();
-    test_int64();
+    if (IS_USED(MODULE_PRINTF_LONG_LONG)) {
+        test_int64();
+    }
+    else {
+        puts("WARNING: Module printf_long_long not used, skipping test for 64 bit");
+    }
     test_size();
     test_flags_widths();