ext/pdo_mysql: Remove PHP/Set

This simplifies configuration and uses less custom modules on the
expense of always visible configuration variable in the GUI. This
variable is also used only in the extension's CMakeLists.txt after
checking whether the pdo_mysql extension is enabled or not.

Author: petk

cmake/ext/pdo_mysql/CMakeLists.txt

@@ -44,7 +44,6 @@ project(
 
 include(CMakeDependentOption)
 include(FeatureSummary)
-include(PHP/Set)
 
 option(PHP_EXT_PDO_MYSQL "Enable the pdo_mysql extension")
 
@@ -63,14 +62,15 @@ cmake_dependent_option(
 )
 
 # Driver selection option.
-php_set(
-  PHP_EXT_PDO_MYSQL_DRIVER
-  CHOICES "mysqlnd" "mysql"
-  IF PHP_EXT_PDO_MYSQL
-  DOC
+set(
+  CACHE{PHP_EXT_PDO_MYSQL_DRIVER}
+  TYPE STRING
+  HELP
     "Select MySQL driver: mysqlnd (MySQL Native Driver, recommended) or mysql "
     "(system MySQL)"
+  VALUE "mysqlnd"
 )
+set_property(CACHE PHP_EXT_PDO_MYSQL_DRIVER PROPERTY STRINGS "mysqlnd" "mysql")
 mark_as_advanced(PHP_EXT_PDO_MYSQL_DRIVER)
 
 if(NOT PHP_EXT_PDO_MYSQL)