package/libxml-parser-perl: make host build use correct compiler

package/libxml-parser-perl: make host build use correct compiler

This package uses gcc filename without absolute path, which breaks
the host build if host and target compiler have the same filename.
(Can happen with an external toolchain).

This patch adds the variables for the host as overrides,
as they are otherwise not picked up from the environment.

Signed-off-by: Norbert Lange <nolange79@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>