* gfortran.h: Add bitmasks for different FPE traps. Add fpe

	* gfortran.h: Add bitmasks for different FPE traps. Add fpe
	member to options_t.
	* invoke.texi: Document the new -ffpe-trap option.
	* lang.opt: Add -ffpe-trap option.
	* options.c (gfc_init_options): Initialize the FPE option.
	(gfc_handle_fpe_trap_option): New function to parse the argument
	of the -ffpe-trap option.
	(gfc_handle_option): Add case for -ffpe-trap.
	* trans-decl.c: Declare a tree for the set_fpe library function.
	(gfc_build_builtin_function_decls): Build this tree.
	(gfc_generate_function_code): Generate a call to set_fpe at
	the beginning of the main program.
	* trans.h: New tree for the set_fpe library function.

	* Makefile.am: Add fpu.c to the build process, and
	target-dependent code as fpu-target.h.
	* Makefile.in: Regenerate.
	* configure.ac: Add call to configure.host to set
	FPU_HOST_HEADER.
	* configure: Regenerate.
	* config.h.in: Regenerate.
	* aclocal.m4: Regenerate.
	* configure.host: New script to determine which host-dependent
	code should go in.
	* libgfortran.h: Add fpe option, remove previous fpu_ options.
	Add bitmasks for different FPE traps. Add prototype for set_fpu.
	* runtime/environ.c: Remove environment variables to control
	fpu behaviour.
	* runtime/fpu.c (set_fpe): New function for the front-end.
	* runtime/main.c (init): Set FPU state.
	* config: New directory to store host-dependent code.
	* config/fpu-387.h: New file with code handling the i387 FPU.
	* config/fpu-glibc.h: New file with code for glibc systems.
	* config/fpu-generic.h: Fallback for the most generic host. Issue
	warnings.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@105328 138bc75d-0d04-0410-961f-82ee72b054a4