fix(pyconfig): X87_double_rounding was reverted

Author: litlighilit

src/pylib/pyconfig/floats.nim

@@ -3,9 +3,9 @@
 import ./util
 
 AC_RUN_IFELSE X87_double_rounding, false:
-  # ref "On IEEE 754, test should return 0 if rounding"
+  # On IEEE 754, test should return 1 if rounding mode is round-to-nearest.
   # maybe following is enough, but I still put origin C code below
-  import std/fenv;quit int(fegetround()!=FE_TONEAREST)
+  import std/fenv;quit int(fegetround()==FE_TONEAREST)
 #[
  Detect whether system arithmetic is subject to x87-style double
  rounding issues.  The result of this test has little meaning on non

src/pylib/pyconfig/util.nim

@@ -71,7 +71,7 @@ proc from_c_int_expr(cacheName, cexpr: string; defval: NimNode): NimNode =
   result = quote do:
     from_c_int(`cexpr`, `defval`):
       {.emit: ["/*VARSECTION*/\n#define ", `pureVarId`, " ", `cexpr`, "\n"].}
-
+#" <- for code lint
 macro from_c_int_underlined*(variable: static[string]; defval: int): int =
   let pureVar = variable.strip(chars = {'_'})
   from_c_int_expr(pureVar, variable, defval)
@@ -107,7 +107,7 @@ template from_c_int*(variable; defvar: int): int =
   bind noop
   from_c_int(variable, defvar, noop)
 
-template AC_LINK_IFELSE*(variable, defval, code) = decl_ac_impl('c', variable, defval, code)
+template AC_LINK_IFELSE*(variable, defval, code) = decl_ac_impl('c', variable, defval, code)  ## variable = whether code exits with 0
 template AC_RUN_IFELSE*(variable, defval, code) = decl_ac_impl(RunSubCmd, variable, defval, code)