RISC-V: Build soft-float divide routines for -mno-fdiv.

Using -mno-fdiv gives linker errors unless we build the missing divide
routines in libgcc always.  There is at least one university project
designing RISC-V parts without FP divide that wants to use the option.

	libgcc/
	* config/riscv/t-softfp32 (softfp_extra): Add FP divide routines

From-SVN: r277723

libgcc/ChangeLog

+2019-11-01  Jim Wilson  <jimw@sifive.com>
+
+	* config/riscv/t-softfp32 (softfp_extra): Add FP divide routines
+
 2019-10-23  Jozef Lawrynowicz  <jozef.l@mittosystems.com>
 
 	* config/msp430/lib2hw_mul.S: Fix wrong syntax in branch instruction.

libgcc/config/riscv/t-softfp32

@@ -12,7 +12,11 @@ softfp_float_modes := tf
 softfp_extensions := sftf dftf
 softfp_truncations := tfsf tfdf
 
+# Enable divide routines to make -mno-fdiv work.
+softfp_extras := divsf3 divdf3
+
 else
+# !ABI_DOUBLE
 
 softfp_float_modes := df tf
 softfp_extensions := sfdf sftf dftf
@@ -20,7 +24,20 @@ softfp_truncations := dfsf tfsf tfdf
 
 ifndef ABI_SINGLE
 softfp_float_modes += sf
+else
+# ABI_SINGLE
+
+# Enable divide routines to make -mno-fdiv work.
+softfp_extras := divsf3
+
 endif
 
 endif
+
+else
+# ABI_QUAD
+
+# Enable divide routines to make -mno-fdiv work.
+softfp_extras := divsf3 divdf3 divtf3
+
 endif