add nofpu subarchs to the sh arch, and properly detect compiler's fpu config

arch/sh/bits/fenv.h

@@ -1,3 +1,10 @@
+#ifndef __SH_FPU_ANY__
+
+#define FE_ALL_EXCEPT 0
+#define FE_TONEAREST  0
+
+#else
+
 #define FE_TONEAREST  0
 #define FE_TOWARDZERO 1
 
@@ -8,6 +15,8 @@
 #define FE_INVALID    0x40
 #define FE_ALL_EXCEPT 0x7c
 
+#endif
+
 typedef unsigned long fexcept_t;
 
 typedef struct {