Fix logging implicit sign conversions

The warnings were being hidden by the use of -isystem to include
frameworks/native/include.

Bug: 31752268
Test: m -j
Change-Id: I2ce11db524ee9d8f846fdf3ed6fb882d5ef57956
(cherry picked from commit 152c3b749a8ec634afc66dddef7d33130472aeb1)
2 files changed