adding a nonblocking mariadb client device

mio/configure

@@ -659,6 +659,8 @@ PACKAGE_VERSION_MINOR
 PACKAGE_VERSION_MAJOR
 QUADMATH_LIBS
 UNWIND_LIBS
+ENABLE_MARIADB_FALSE
+ENABLE_MARIADB_TRUE
 SSL_LIBS
 UNICOWS_LIBS
 SENDFILE_LIBS
@@ -804,6 +806,7 @@ with_gnu_ld
 with_sysroot
 enable_libtool_lock
 enable_ssl
+enable_mariadb
 enable_debug
 enable_unicode
 enable_cxx
@@ -1453,6 +1456,7 @@ Optional Features:
                           optimize for fast installation [default=yes]
   --disable-libtool-lock  avoid locking (might break parallel builds)
   --enable-ssl            build the library in the ssl mode (default. yes)
+  --enable-mariadb        enable mariadb support (default. no)
   --enable-debug          build the library in the debug mode (default. no)
   --enable-unicode        Use the unicode character type as the default
                           character type. one of yes, no, yes:2, yes:4, no:2,
@@ -18638,6 +18642,30 @@ done
 fi
 
 
+# Check whether --enable-mariadb was given.
+if test "${enable_mariadb+set}" = set; then :
+  enableval=$enable_mariadb; enable_mariadb_is=$enableval
+else
+  enable_mariadb_is=no
+
+fi
+
+if test "${enable_mariadb_is}" = "yes"
+then
+
+$as_echo "#define MIO_ENABLE_MARIADB 1" >>confdefs.h
+
+fi
+ if test "${enable_mariadb_is}" = "yes"; then
+  ENABLE_MARIADB_TRUE=
+  ENABLE_MARIADB_FALSE='#'
+else
+  ENABLE_MARIADB_TRUE='#'
+  ENABLE_MARIADB_FALSE=
+fi
+
+
+
 if test "x${ac_cv_header_libunwind_h}" = "xyes"
 then
 	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for unw_backtrace in -lunwind" >&5
@@ -21930,6 +21958,10 @@ if test -z "${MACOSX_TRUE}" && test -z "${MACOSX_FALSE}"; then
   as_fn_error $? "conditional \"MACOSX\" was never defined.
 Usually this means the macro was only invoked conditionally." "$LINENO" 5
 fi
+if test -z "${ENABLE_MARIADB_TRUE}" && test -z "${ENABLE_MARIADB_FALSE}"; then
+  as_fn_error $? "conditional \"ENABLE_MARIADB\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
 
 if test -z "${ENABLE_CXX_TRUE}" && test -z "${ENABLE_CXX_FALSE}"; then
   as_fn_error $? "conditional \"ENABLE_CXX\" was never defined.