Add -Wclass-conversion.

Add -Wclass-conversion.

	* c.opt (Wclass-conversion): New.

	* decl.c (grok_op_properties): Change a warning from -Wconversion to
	-Wclass-conversion.  Make it print the types.

	* doc/invoke.texi: Document -Wclass-conversion.

	* g++.dg/conversion/op4.C: Add dg-warning.
	* g++.dg/warn/Wclass-conversion1.C: New test.
	* g++.dg/warn/Wclass-conversion2.C: New test.
	* g++.dg/warn/Wconversion5.C: Remove file.
	* g++.dg/warn/conversion-function-1.C: Use -Wno-class-converison.
	* g++.old-deja/g++.bugs/900215_01.C: Adjust dg-warning.
	* g++.old-deja/g++.jason/conversion5.C: Likewise.

From-SVN: r264438