PR fortran/26025

	* lang.opt: Add -fexternal-blas and -fblas-matmul-limit options.
	* options.c (gfc_init_options): Initialize new flags.
	(gfc_handle_option): Handle new flags.
	* gfortran.h (gfc_option): Add flag_external_blas and
	blas_matmul_limit flags.
	* trans-expr.c (gfc_conv_function_call): Use new argument
	append_args, appending it at the end of the argument list
	built for a function call.
	* trans-stmt.c (gfc_trans_call): Use NULL_TREE for the new
	append_args argument to gfc_trans_call.
	* trans.h (gfc_conv_function_call): Update prototype.
	* trans-decl.c (gfc_build_intrinsic_function_decls): Add
	prototypes for BLAS ?gemm routines.
	* trans-intrinsic.c (gfc_conv_intrinsic_funcall): Generate the
	extra arguments given to the library matmul function, and give
	them to gfc_conv_function_call.
	* invoke.texi: Add documentation for -fexternal-blas and
	-fblas-matmul-limit.

	* m4/matmul.m4: Add possible call to gemm routine.
	* generated/matmul_r8.c: Regenerate.
	* generated/matmul_r16.c: Regenerate.
	* generated/matmul_c8.c: Regenerate.
	* generated/matmul_i8.c: Regenerate.
	* generated/matmul_c16.c: Regenerate.
	* generated/matmul_r10.c: Regenerate.
	* generated/matmul_r4.c: Regenerate.
	* generated/matmul_c10.c: Regenerate.
	* generated/matmul_c4.c: Regenerate.
	* generated/matmul_i4.c: Regenerate.
	* generated/matmul_i16.c: Regenerate.

From-SVN: r117948