PR fortran/25252

	* interface.c (gfc_current_interface_head,
	gfc_set_current_interface_head): New functions.
	* decl.c (gfc_match_modproc): Move check for syntax error earlier.
	On syntax error, restore previous state of the interface.
	* gfortran.h (gfc_current_interface_head,
	gfc_set_current_interface_head): New prototypes.

	* gfortran.dg/interface_22.f90: New test.

From-SVN: r130259