make lz4_decompress
/utilities/lz4_decompress.cc: In function main:
/lz4/lz4frame.c:1282:47: warning:
decompression_context may be used uninitialized in this function [-Wmaybe-uninitialized]

make mysql
/extra/libedit/readline.c: In function readline:
/extra/libedit/read.c:270:21: warning: variable val might be clobbered by longjmp or vfork [-Wclobbered]
    keymacro_value_t val;
                     ^
/sql-common/client.cc: In function cli_advanced_command:
/sql-common/net_serv.cc:1114:10: warning: compr_length may be used uninitialized in this function [-Wmaybe-uninitialized]
   size_t compr_length;

make mysqld
/storage/heap/ha_heap.cc: In member function info:
/storage/heap/ha_heap.cc:368: warning: hp_info.auto_increment may be used uninitialized in this function [-Wmaybe-uninitialized]
     stats.auto_increment_value = hp_info.auto_increment;

Change-Id: Ie043b8bba71eeba2821eed579fe04b9684d6a0fc