msvcrt: Import ceil implementation from musl.

dlls/msvcrt/math.c

@@ -1740,10 +1740,31 @@ float CDECL _hypotf(float x, float y)
 
 /*********************************************************************
  *		ceil (MSVCRT.@)
+ *
+ * Based on musl: src/math/ceilf.c
  */
 double CDECL ceil( double x )
 {
-  return unix_funcs->ceil(x);
+    union {double f; UINT64 i;} u = {x};
+    int e = (u.i >> 52 & 0x7ff) - 0x3ff;
+    UINT64 m;
+
+    if (e >= 52)
+        return x;
+    if (e >= 0) {
+        m = 0x000fffffffffffffULL >> e;
+        if ((u.i & m) == 0)
+            return x;
+        if (u.i >> 63 == 0)
+            u.i += m;
+        u.i &= ~m;
+    } else {
+        if (u.i >> 63)
+            return -0.0;
+        else if (u.i << 1)
+            return 1.0;
+    }
+    return u.f;
 }
 
 /*********************************************************************

dlls/msvcrt/unixlib.c

@@ -122,14 +122,6 @@ static float CDECL unix_atanhf(float x)
 }
 
 /*********************************************************************
- *      ceil
- */
-static double CDECL unix_ceil( double x )
-{
-    return ceil( x );
-}
-
-/*********************************************************************
  *      ceilf
  */
 static float CDECL unix_ceilf( float x )
@@ -713,7 +705,6 @@ static const struct unix_funcs funcs =
     unix_asinhf,
     unix_atanh,
     unix_atanhf,
-    unix_ceil,
     unix_ceilf,
     unix_cos,
     unix_cosf,

dlls/msvcrt/unixlib.h

@@ -29,7 +29,6 @@ struct unix_funcs
     float           (CDECL *asinhf)(float x);
     double          (CDECL *atanh)(double x);
     float           (CDECL *atanhf)(float x);
-    double          (CDECL *ceil)(double x);
     float           (CDECL *ceilf)(float x);
     double          (CDECL *cos)(double x);
     float           (CDECL *cosf)(float x);