../../libraries/AP_HAL/examples/Printf/Printf.cpp:63:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if (ret != strlen(float_tests[i].result)) {
^
...
ardupilot/modules/gtest/include/gtest/gtest.h:1448:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if (expected == actual) {
^
And similar ones.