Win32: Drop support for older than MSVC 9.0/_MSC_VER 1500

Visual C++ 2008 (9.0):
- _MSC_VER: 1500
- MSVCRT_VERSION: 90

configure.ac

@@ -526,7 +526,7 @@ AS_CASE(["$target_os"],
 	RT_VER=`echo "$rb_cv_msvcrt" | tr -cd [0-9]`
 	test "$RT_VER" = "" && RT_VER=60
 	test "$rb_cv_msvcrt" = "ucrt" && RT_VER=140
-	AS_IF([test $RT_VER -lt 80], AC_MSG_ERROR(Runtime library $RT_VER is not supported))
+	AS_IF([test $RT_VER -lt 90], AC_MSG_ERROR(Runtime library $RT_VER is not supported))
 	AC_DEFINE_UNQUOTED(RUBY_MSVCRT_VERSION, $RT_VER)
 	sysconfdir=
     ])

ext/socket/rubysocket.h

@@ -510,8 +510,6 @@ extern ID tcp_fast_fallback;
 const char *inet_ntop(int, const void *, char *, size_t);
 #elif defined __MINGW32__
 # define inet_ntop(f,a,n,l)      rb_w32_inet_ntop(f,a,n,l)
-#elif defined _MSC_VER && RUBY_MSVCRT_VERSION < 90
-const char *WSAAPI inet_ntop(int, const void *, char *, size_t);
 #endif
 
 #endif

regint.h

@@ -215,9 +215,7 @@
 #define xmemcpy     memcpy
 #define xmemmove    memmove
 
-#if ((defined(RUBY_MSVCRT_VERSION) && RUBY_MSVCRT_VERSION >= 90) \
-        || (!defined(RUBY_MSVCRT_VERSION) && defined(_WIN32))) \
-    && !defined(__GNUC__)
+#if defined(_WIN32) && !defined(__GNUC__)
 # define xalloca     _alloca
 # define xvsnprintf(buf,size,fmt,args)  _vsnprintf_s(buf,size,_TRUNCATE,fmt,args)
 # define xsnprintf   sprintf_s

win32/Makefile.sub

@@ -132,7 +132,7 @@ CAT_DEPEND = type
 
 !if !defined(MSC_VER)
 ! error MSC_VER not defined.  Retry from configure pass.
-!else if $(MSC_VER) < 1400
+!else if $(MSC_VER) < 1500
 ! error MSVC $(MSC_VER) is not supported
 !endif
 !if !defined(MACHINE)
@@ -174,7 +174,7 @@ PLATFORM = mswin32
 !endif
 !if !defined(RT)
 !error RT not defined.  Retry from configure pass.
-!else if $(RT_VER) < 80
+!else if $(RT_VER) < 90
 ! error Runtime library $(RT_VER) is not supported
 !endif
 !ifndef NTVER
@@ -749,11 +749,9 @@ $(CONFIG_H): $(MKFILES) $(srcdir)/win32/Makefile.sub $(win_srcdir)/Makefile.sub
 #define FUNC_STDCALL(x) __stdcall x
 #define FUNC_CDECL(x) __cdecl x
 #define FUNC_FASTCALL(x) __fastcall x
-!if $(MSC_VER) >= 1500
 #define RUBY_FUNCTION_NAME_STRING __FUNCTION__
 #define RBIMPL_ATTR_PACKED_STRUCT_BEGIN() __pragma(pack(push, 1))
 #define RBIMPL_ATTR_PACKED_STRUCT_END() __pragma(pack(pop))
-!endif
 #define RUBY_EXTERN extern __declspec(dllimport)
 #define RUBY_FUNC_EXPORTED extern __declspec(dllexport)
 #define RUBY_ALIGNAS(n) __declspec(align(n))

win32/win32.c

@@ -21,9 +21,9 @@
 
 #undef __STRICT_ANSI__
 
-/* Visual C++ 2005 (8.0):
- * - _MSC_VER: 1400
- * - MSVCRT_VERSION: 80
+/* Visual C++ 2008 (9.0):
+ * - _MSC_VER: 1500
+ * - MSVCRT_VERSION: 90
  */
 #include "ruby/ruby.h"
 #include "ruby/encoding.h"