fix bison warnings (clash <NONE> != <>)
.gitignore ninja files
MDEV-6107 merge default_tmp_storage_engine

Adapt default_tmp_storage_engine implementation from mysql-5.6
New feature (as compared to 5.6), default_tmp_storage_engine=NULL
means that temporary tables will use default_storage_engine value.
This makes the behavior backward compatible.
Fixed test failure introduced by adding a new dynamic
configuration variable innodb_compression_algorithm.
Removed unnecessary test for removed configuration
variable.
Merge branch '10.1' of github.com:MariaDB/server into 10.1
cmake: prefer INSTALL(PROGRAMS over INSTALL(FILES
cmake cleanup: use MY_CHECK_AND_SET_COMPILER_FLAG.

move MY_CHECK_C_COMPILER_FLAG and MY_CHECK_CXX_COMPILER_FLAG
to a separate file, introduce MY_CHECK_AND_SET_COMPILER_FLAG,
use it where possible.
MDEV-5730 enhance security using special compilation options

-Wl,-z,relro,-z,now
-pie
-fstack-protector --param=ssp-buffer-size=4
-D_FORTIFY_SOURCE=2
remove unused sql/examples