* intrinsic.c (add_conv): No longer take a "simplify" argument as
	its always gfc_convert_constant, instead take a "standard" argument.
	(add_conversions): Change all existing calls of add_conv to pass
	GFC_STD_F77 as appropriate.  Additionally, if we're allowing GNU
	extensions support integer-logical and logical-integer conversions.
	(gfc_convert_type_warn): Warn about use the use of these conversions
	as a extension when appropriate, i.e. with -pedantic.
	* simplify.c (gfc_convert_constant): Add support for integer to
	logical and logical to integer conversions, using gfc_int2log and
	gfc_log2int.
	* arith.c (gfc_log2int, gfc_int2log): New functions.
	* arith.h (gfc_log2int, gfc_int2log): Prototype here.
	* gfortran.texi: Document this new GNU extension.

	* gfortran.dg/logint-1.f: New test case.
	* gfortran.dg/logint-2.f: Likewise.
	* gfortran.dg/logint-3.f: Likewise.

From-SVN: r100461