According to http://postgis.net/docs/manual-1.3/ch06.html

We still don't have:

(MDEV-7515) AddGeometryColumn(varchar, varchar, varchar, integer, varchar, integer)
Syntax: AddGeometryColumn(<schema_name>, <table_name>, <column_name>, <srid>, <type>, <dimension>). Adds a geometry column to an existing table of attributes. The schema_name is the name of the table schema (unused for pre-schema PostgreSQL installations). The srid must be an integer value reference to an entry in the SPATIAL_REF_SYS table. The type must be an uppercase string corresponding to the geometry type, eg, 'POLYGON' or 'MULTILINESTRING'.

(MDEV-7515) DropGeometryColumn(varchar, varchar, varchar)
Syntax: DropGeometryColumn(<schema_name>, <table_name>, <column_name>). Remove a geometry column from a spatial table. Note that schema_name will need to match the f_schema_name field of the table's row in the geometry_columns table.

Probe_Geometry_Columns()
Scans all tables with PostGIS geometry constraints and adds them to the geometry_columns table if they are not already there. Also give stats on the number of inserts, already present, or possibly obsolete columns.

ST_SetSRID(geometry, integer)
Set the SRID on a geometry to a particular integer value. Useful in constructing bounding boxes for queries.

ST_DWithin(geometry, geometry, float)
Returns true if geometries are within the specified distance of one another. Uses indexes if available.

ST_Shift_Longitude(geometry)
Reads every point/vertex in every component of every feature in a geometry, and if the longitude coordinate is <0, adds 360 to it. The result would be a 0-360 version of the data to be plotted in a 180 centric map

ST_NumInteriorRing(geometry)
Synonym to NumInteriorRings(geometry).

ST_Z(geometry)
Return the Z coordinate of the point, or NULL if not available. Input must be a point.

ST_MPointFromText(text,[<srid>])
Makes a Geometry from WKT with the given SRID. If SRID is not give, it defaults to -1.

ST_MLineFromText(text,[<srid>])
Makes a Geometry from WKT with the given SRID. If SRID is not give, it defaults to -1.

ST_MPolyFromText(text,[<srid>])
Makes a Geometry from WKT with the given SRID. If SRID is not give, it defaults to -1.

ST_MPointFromWKB(bytea,[<srid>])
Makes a Geometry from WKB with the given SRID. If SRID is not give, it defaults to -1.

ST_MLineFromWKB(bytea,[<srid>])
Makes a Geometry from WKB with the given SRID. If SRID is not give, it defaults to -1.

ST_MPolyFromWKB(bytea,[<srid>])
Makes a Geometry from WKB with the given SRID. If SRID is not give, it defaults to -1.

ST_BdPolyFromText(text WKT, integer SRID)
Construct a Polygon given an arbitrary collection of closed linestrings as a MultiLineString text representation.

ST_BdMPolyFromText(text WKT, integer SRID)
Construct a MultiPolygon given an arbitrary collection of closed linestrings as a MultiLineString text representation.

Note that in the description of the SPATIAL_REF_SYS table, it looks like some text was chopped off. The text probably should read:

  SRID INTEGER NOT NULL PRIMARY KEY,

            an integer value that uniquely identifies each Spatial Reference System within a database.

  AUTH_NAME CHARACTER VARYING(256),

            the name of the standard or standards body that is being cited for this reference system.

            In most cases the value is "EPSG".

  AUTH_SRID INTEGER 

           the numeric ID of the coordinate system in the above authority's catalog.

  SRTEXT TEXT

            the Well-known Text Representation of the Spatial Reference System.

See also https://mariadb.atlassian.net/browse/MDEV-7540