some cleanups related to recent commits

- configure/Makefile : cleanup, really use CC_NAME
- tccasm.c : remove C99 construct that MSVC doesn't compile
- arm-gen.c, x86_64-gen.c, riscv64-gen.c, tccmacho.c : ditto
- arm64-gen.c: commit 383acf8eff wrote:
  "Instead of a cast, it would be better to pass the exact type."
  It is true that there are better solutions but it is not
  passing the exact type (I think).
- tcctest.c: revert "fix cast test for clang" 03646ad46f
  this obviously wants to test non-portable conversions
- 114_bound_signal.test: clock_nanosleep is too new for older
  linuxes, just use sleep() instead

tccgen.c

@@ -4978,7 +4978,7 @@ the_end:
     bt = t & (VT_BTYPE|VT_LONG);
     if (bt == VT_LONG)
         t |= LONG_SIZE == 8 ? VT_LLONG : VT_INT;
-#ifdef TCC_TARGET_PE
+#if defined TCC_TARGET_PE || (defined _WIN32 && defined _MSC_VER)
     if (bt == VT_LDOUBLE)
         t = (t & ~(VT_BTYPE|VT_LONG)) | (VT_DOUBLE|VT_LONG);
 #endif