crt: crt_handler: Move __mingw_init_ehandler specific definitions into appropriate ifdef section

Do not declare structures and functions specific to __mingw_init_ehandler
when not compiling __mingw_init_ehandler at all.

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

mingw-w64-crt/crt/crt_handler.c

diff --git a/mingw-w64-crt/crt/crt_handler.c b/mingw-w64-crt/crt/crt_handler.c
index 1d9367b..636b901 100644
--- a/mingw-w64-crt/crt/crt_handler.c
+++ b/mingw-w64-crt/crt/crt_handler.c
@@ -13,6 +13,8 @@
 #include <signal.h>
 #include <stdio.h>
 
+#if defined(__x86_64__) && !defined(_MSC_VER) && !defined(__SEH__)
+
 #pragma pack(push,1)
 typedef struct _UNWIND_INFO {
   BYTE VersionAndFlags;
@@ -27,16 +29,13 @@
 PIMAGE_SECTION_HEADER _FindPESectionExec (size_t);
 PBYTE _GetPEImageBase (void);
 
-int __mingw_init_ehandler (void);
-extern void _fpreset (void);
-
-#if defined(__x86_64__) && !defined(_MSC_VER) && !defined(__SEH__)
 EXCEPTION_DISPOSITION __cdecl __mingw_SEH_error_handler(struct _EXCEPTION_RECORD *, void *, struct _CONTEXT *, void *);
 
 #define MAX_PDATA_ENTRIES 32
 static RUNTIME_FUNCTION emu_pdata[MAX_PDATA_ENTRIES];
 static UNWIND_INFO emu_xdata[MAX_PDATA_ENTRIES];
 
+int __mingw_init_ehandler (void);
 int
 __mingw_init_ehandler (void)
 {