add @CMAKE_SYSROOT@ to include and library paths

When cross-compiling MariaDB, system paths are returned by the mysql-config
and mariadb-config tools. Add @CMAKE_SYSROOT@ to the paths to avoid this
issue.

Signed-off-by: Ryan Coe <bluemrp9@gmail.com>

mariadb_config/mariadb_config.c.in

@@ -5,8 +5,8 @@
 
 static char *mariadb_progname;
 
-#define INCLUDE "-I@CMAKE_INSTALL_PREFIX@/@INSTALL_INCLUDEDIR@ -I@CMAKE_INSTALL_PREFIX@/@INSTALL_INCLUDEDIR@/mysql"
-#define LIBS    "-L@CMAKE_INSTALL_PREFIX@/@INSTALL_LIBDIR@/ -lmariadb"
+#define INCLUDE "-I@CMAKE_SYSROOT@@CMAKE_INSTALL_PREFIX@/@INSTALL_INCLUDEDIR@ -I@CMAKE_SYSROOT@@CMAKE_INSTALL_PREFIX@/@INSTALL_INCLUDEDIR@/mysql"
+#define LIBS    "-L@CMAKE_SYSROOT@@CMAKE_INSTALL_PREFIX@/@INSTALL_LIBDIR@/ -lmariadb"
 #define LIBS_SYS "@extra_dynamic_LDFLAGS@"
 #define CFLAGS  INCLUDE
 #define VERSION "@MARIADB_CLIENT_VERSION@"