crt: Move dummy __setusermatherr() function into misc/dummy__setusermatherr.c file.

It would be used also in followup changes.

Signed-off-by: LIU Hao <lh_mouse@126.com>

mingw-w64-crt/Makefile.am

diff --git a/mingw-w64-crt/Makefile.am b/mingw-w64-crt/Makefile.am
index 9643871..971c335 100644
--- a/mingw-w64-crt/Makefile.am
+++ b/mingw-w64-crt/Makefile.am
@@ -425,6 +425,7 @@
   misc/__p__commode.c \
   misc/__p__fmode.c \
   misc/__set_app_type.c \
+  misc/dummy__setusermatherr.c \
   misc/invalid_parameter_handler.c \
   misc/lc_locale_func.c \
   misc/seterrno.c \

mingw-w64-crt/crt/crtdll_compat.c

diff --git a/mingw-w64-crt/crt/crtdll_compat.c b/mingw-w64-crt/crt/crtdll_compat.c
index 39cc300..0f0b8d4 100644
--- a/mingw-w64-crt/crt/crtdll_compat.c
+++ b/mingw-w64-crt/crt/crtdll_compat.c
@@ -5,11 +5,6 @@
  */
 
 #include <internal.h>
-#include <math.h>
-
-/* Define dummy __setusermatherr() function as crtdll.dll does not provide it */
-#undef __setusermatherr
-void __setusermatherr(__UNUSED_PARAM(int (__cdecl *f)(struct _exception *))) { }
 
 /* Define __getmainargs() function via crtdll.dll __GetMainArgs() function */
 extern void __GetMainArgs(int *argc, char ***argv, char ***envp, int expand_wildcards);

mingw-w64-crt/misc/dummy__setusermatherr.c

diff --git a/mingw-w64-crt/misc/dummy__setusermatherr.c b/mingw-w64-crt/misc/dummy__setusermatherr.c
new file mode 100644
index 0000000..3442786
--- /dev/null
+++ b/mingw-w64-crt/misc/dummy__setusermatherr.c
@@ -0,0 +1,11 @@
+/**
+ * This file has no copyright assigned and is placed in the Public Domain.
+ * This file is part of the mingw-w64 runtime package.
+ * No warranty is given; refer to the file DISCLAIMER.PD within this package.
+ */
+
+#include <internal.h>
+#include <math.h>
+
+#undef __setusermatherr
+void __setusermatherr(__UNUSED_PARAM(int (__cdecl *f)(struct _exception *))) { }