Add -Wall to gcc/g++
Fix most warnings reported in dbg and opt mode.


cmd-line-utils/libedit/filecomplete.c:
  Remove unused auto variables.
configure.cmake:
  Add -Wall to gcc.
extra/comp_err.c:
  Cast to correct type.
extra/perror.c:
  Fix segfault (but warnings about deprecated features remain)
extra/yassl/taocrypt/include/runtime.hpp:
  Comparing two literals was reported as undefined behaviour.
include/my_global.h:
  Add a template for aligning character buffers.
mysys/lf_alloc-pin.c:
  Initialize pointer.
sql/mysqld.cc:
  Use UNINIT_VAR rather than LINT_INIT.
sql/partition_info.cc:
  Use UNINIT_VAR rather than LINT_INIT.
sql/rpl_handler.cc:
  Use char[] rather than unsigned long[] array for placement buffer.
sql/spatial.cc:
  Use char[] rather than unsigned void*[] array for placement buffer.
sql/spatial.h:
  Use char[] rather than unsigned void*[] array for placement buffer.
sql/sql_partition.cc:
  Initialize auto variable.
sql/sql_table.cc:
  Initialize auto variables.
  Add parens around assignment within if()
sql/sys_vars.cc:
  Use UNINIT_VAR.
storage/innobase/os/os0file.c:
  Init first slot in auto variable.
storage/myisam/mi_create.c:
  Use UNINIT_VAR rather than LINT_INIT.
storage/myisam/mi_open.c:
  Remove (wrong) casting.
storage/myisam/mi_page.c:
  Remove (wrong) casting.
storage/myisam/mi_search.c:
  Cast to uchar* rather than char*.
strings/ctype-ucs2.c:
  Use UNINIT_VAR rather than LINT_INIT.
  Add (uchar*) casting.