C-SKY: Strip hard float abi from hard float feature.

The hard float abi and hard float are different,
  Hard float abi: Use float register to pass float type arguments.
  Hard float: Enable the hard float ISA feature.
So the with_fp_cond cannot represent these two features. When
-mfloat-abi=softfp, the float abi is soft and hard float is enabled.
So add 'with_hard_float_abi' in preconfigure and define 'CSKY_HARD_FLOAT_ABI'
if float abi is hard, and use 'CSKY_HARD_FLOAT_ABI' to determine
dynamic linker because it is what determines compatibility.
And with_fp_cond is still needed to tell glibc whether to enable
hard floating feature.
In addition, use AC_TRY_COMMAND to test gcc to ensure compatibility
between different versions of gcc. The original way has a problem
that __CSKY_HARD_FLOAT_FPU_SF__ means the target only has single
hard float-points ISA, so it's not defined in CPUs like ck810f.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/config.h.in b/config.h.in
index 43d3251..09730d9 100644
--- a/config.h.in
+++ b/config.h.in
@@ -123,9 +123,12 @@
 /* C-SKY ABI version.  */
 #undef CSKYABI
 
-/* C-SKY floating-point ABI.  */
+/* C-SKY floating-point instructions.  */
 #undef CSKY_HARD_FLOAT
 
+/* C-SKY floating-point ABI.  */
+#undef CSKY_HARD_FLOAT_ABI
+
 /* RISC-V integer ABI for ld.so.  */
 #undef RISCV_ABI_XLEN