[arm] PR target/83105: Minor change of default CPU for arm-linux-gnueabi

When GCC for ARM/linux is configured with --with-float=hard, or
--with-float=softfp the compiler will now die when trying to build the
support libraries because the baseline architecture is too old to
support VFP (older versions of GCC just emitted the VFP instructions
anyway, even though they wouldn't run on that version of the
architecture; but we're now more prickly about it).

This patch fixed the problem by raising the default architecture
(actually the default CPU) to ARMv5te (ARM10e) when we need to generate
HW floating-point code.

	PR target/83105
	* config.gcc (arm*-*-linux*): When configured with --with-float=hard
	or --with-float=softfp, set the default CPU to arm10e.

From-SVN: r255858

gcc/ChangeLog

+2017-12-20  Richard Earnshaw  <rearnsha@arm.com>
+
+	PR target/83105
+	* config.gcc (arm*-*-linux*): When configured with --with-float=hard
+	or --with-float=softfp, set the default CPU to arm10e.
+
 2017-12-20  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* config/visium/constraints.md (J, K, L): Use IN_RANGE macro.

gcc/config.gcc

@@ -1134,7 +1134,12 @@ arm*-*-linux-*)			# ARM GNU/Linux with ELF
 	esac
 	tmake_file="${tmake_file} arm/t-arm arm/t-arm-elf arm/t-bpabi arm/t-linux-eabi"
 	tm_file="$tm_file arm/bpabi.h arm/linux-eabi.h arm/aout.h vxworks-dummy.h arm/arm.h"
-	target_cpu_cname="arm10tdmi"
+	# Generation of floating-point instructions requires at least ARMv5te.
+	if [ "$with_float" = "hard" -o "$with_float" = "softfp" ] ; then
+	    target_cpu_cname="arm10e"
+	else
+	    target_cpu_cname="arm10tdmi"
+	fi
 	# Define multilib configuration for arm-linux-androideabi.
 	case ${target} in
 	*-androideabi)