[CRT] Fix _matherror and _setusermatherror

We previously used 2 different versions: one from wine and one from mingw-w64.
The former was used in msvcrt, the latter was statically compiled into the executable. When using MS libs, there is only one _matherr, which is statically linked into the executable and does nothing (it's not really a function for users to be called).
_setusermatherror should only exist in msvcrt and not statically, which wouldn't work at all.

sdk/lib/crt/except/except.cmake

@@ -55,7 +55,6 @@ endif()
 
 list(APPEND CRT_EXCEPT_SOURCE
     ${LIBCNTPR_EXCEPT_SOURCE}
-    except/matherr.c
     except/stack.c
 )
 

sdk/lib/crt/except/matherr.c

@@ -1,49 +0,0 @@
-#include <precomp.h>
-
-#define __USE_ISOC9X 1
-#define __USE_ISOC99 1
-#include <math.h>
-
-#ifdef HAVE_IEEEFP_H
-#include <ieeefp.h>
-#endif
-
-#ifndef HAVE_FINITE
-#ifndef finite /* Could be a macro */
-#ifdef isfinite
-#define finite(x) isfinite(x)
-#else
-#define finite(x) (!isnan(x)) /* At least catch some cases */
-#endif
-#endif
-#endif
-
-#ifndef signbit
-#define signbit(x) 0
-#endif
-
-typedef int (*MSVCRT_matherr_func)(struct _exception *);
-
-static MSVCRT_matherr_func MSVCRT_default_matherr_func = NULL;
-
-int CDECL _matherr(struct _exception *e)
-{
-  if (e)
-    TRACE("(%p = %d, %s, %g %g %g)\n",e, e->type, e->name, e->arg1, e->arg2,
-          e->retval);
-  else
-    TRACE("(null)\n");
-  if (MSVCRT_default_matherr_func)
-    return MSVCRT_default_matherr_func(e);
-  ERR(":Unhandled math error!\n");
-  return 0;
-}
-
-/*********************************************************************
- *		__setusermatherr (MSVCRT.@)
- */
-void CDECL __setusermatherr(MSVCRT_matherr_func func)
-{
-  MSVCRT_default_matherr_func = func;
-  TRACE(":new matherr handler %p\n", func);
-}

sdk/lib/crt/math/math.cmake

@@ -3,6 +3,7 @@ list(APPEND LIBCNTPR_MATH_SOURCE
     math/abs.c
     math/div.c
     math/labs.c
+    math/usermatherr.c
 )
 
 if(ARCH STREQUAL "i386")

sdk/lib/crt/math/usermatherr.c

@@ -0,0 +1,36 @@
+/*
+ * PROJECT:     ReactOS CRT library
+ * LICENSE:     MIT (https://spdx.org/licenses/MIT)
+ * PURPOSE:     Implementation of __setusermatherr and _invoke_user_matherr
+ * COPYRIGHT:   Copyright 2021 Timo Kreuzer <timo.kreuzer@reactos.org>
+ */
+
+// DO NOT SYNC WITH WINE OR MINGW32
+
+#include <math.h>
+
+/* MS headers have this in corecrt_startup.h */
+typedef int (*_UserMathErrorFunctionPointer)(struct _exception *);
+
+static _UserMathErrorFunctionPointer user_matherr = NULL;;
+
+void
+__cdecl
+__setusermatherr(_UserMathErrorFunctionPointer func)
+{
+    user_matherr = func;
+}
+
+int
+__cdecl
+_invoke_user_matherr(struct _exception *e)
+{
+    if (user_matherr != NULL)
+    {
+        return user_matherr(e);
+    }
+    else
+    {
+        return 0;
+    }
+}

sdk/lib/crt/msvcrtex.cmake

@@ -2,6 +2,7 @@
 include_directories(include/internal/mingw-w64)
 
 list(APPEND MSVCRTEX_SOURCE
+    startup/_matherr.c
     startup/crtexe.c
     startup/wcrtexe.c
     startup/crt_handler.c
@@ -12,7 +13,6 @@ list(APPEND MSVCRTEX_SOURCE
     startup/mingw_helpers.c
     startup/natstart.c
     startup/charmax.c
-    startup/merr.c
     startup/atonexit.c
     startup/dllmain.c
     startup/txtmode.c

sdk/lib/crt/startup/_matherr.c

@@ -0,0 +1,18 @@
+/*
+ * PROJECT:     ReactOS CRT library
+ * LICENSE:     MIT (https://spdx.org/licenses/MIT)
+ * PURPOSE:     Implementation of _matherr dummy
+ * COPYRIGHT:   Copyright 2021 Timo Kreuzer <timo.kreuzer@reactos.org>
+ */
+
+// DO NOT SYNC WITH WINE OR MINGW32
+
+#include <math.h>
+
+/* Dummy function, like in MS CRT */
+int
+__cdecl
+_matherr(struct _exception *pexcept)
+{
+    return 0;
+}

sdk/lib/crt/startup/merr.c

@@ -1,76 +0,0 @@
-/**
- * This file has no copyright assigned and is placed in the Public Domain.
- * This file is part of the w64 mingw-runtime package.
- * No warranty is given; refer to the file DISCLAIMER.PD within this package.
- */
-
-#include <internal.h>
-#include <math.h>
-#include <stdio.h>
-
-typedef int (__cdecl *fUserMathErr)(struct _exception *);
-static fUserMathErr stUserMathErr;
-
-void __mingw_raise_matherr (int typ, const char *name, double a1, double a2,
-			    double rslt)
-{
-  struct _exception ex;
-  if (!stUserMathErr)
-    return;
-  ex.type = typ;
-  ex.name = (char*)name;
-  ex.arg1 = a1;
-  ex.arg2 = a2;
-  ex.retval = rslt;
-  (*stUserMathErr)(&ex);
-}
-
-#undef __setusermatherr
-
-void __mingw_setusermatherr (int (__cdecl *f)(struct _exception *))
-{
-  stUserMathErr = f;
-  __setusermatherr (f);
-}
-
-int __CRTDECL
-_matherr (struct _exception *pexcept)
-{
-  const char * type;
-
-  switch(pexcept->type)
-    {
-      case _DOMAIN:
-	type = "Argument domain error (DOMAIN)";
-	break;
-
-      case _SING:
-	type = "Argument singularity (SIGN)";
-	break;
-
-      case _OVERFLOW:
-	type = "Overflow range error (OVERFLOW)";
-	break;
-
-      case _PLOSS:
-	type = "Partial loss of significance (PLOSS)";
-	break;
-
-      case _TLOSS:
-	type = "Total loss of significance (TLOSS)";
-	break;
-
-      case _UNDERFLOW:
-	type = "The result is too small to be represented (UNDERFLOW)";
-	break;
-
-      default:
-	type = "Unknown error";
-	break;
-    }
-
-  __mingw_fprintf (stderr, "_matherr(): %s in %s(%g, %g)  (retval=%g)\n",
-	  type, pexcept->name, pexcept->arg1, pexcept->arg2, pexcept->retval);
-  return 0;
-}
-

sdk/lib/crt/startup/startup.cmake

@@ -1,5 +1,6 @@
 
 list(APPEND CRT_STARTUP_SOURCE
+    startup/_matherr.c
     startup/crtexe.c
     startup/wcrtexe.c
     startup/crt_handler.c
@@ -10,7 +11,6 @@ list(APPEND CRT_STARTUP_SOURCE
     startup/mingw_helpers.c
     startup/natstart.c
     startup/charmax.c
-    #startup/merr.c
     startup/atonexit.c
     #startup/txtmode.c
     startup/pesect.c