zlib: patches for mswin64

* cast to suppress C4267 warnings; no possible loss of data as
  following the comparison.

* shift base address to suppress LNK4281; although /DYNAMICBASE is
  preferable, not sure from which version of link.exe supports it.

ext/zlib/extconf.rb

@@ -31,9 +31,12 @@ else
       $extso << dll
       $cleanfiles << "$(topdir)/#{dll}" << "$(ZIMPLIB)"
       zmk = "\t$(MAKE) -f $(ZMKFILE) TOP=$(ZSRC)"
+      zopts = []
       if $nmake
         zmkfile = "$(ZSRC)/win32/Makefile.msc"
         m = "#{zsrc}/win32/Makefile.msc"
+        # zopts << "USE_ASM=1"
+        zopts << "ARCH=#{RbConfig::CONFIG['target_cpu']}"
       else
         zmkfile = "$(ZSRC)/win32/Makefile.gcc"
         m = "#{zsrc}/win32/Makefile.gcc"
@@ -55,9 +58,10 @@ else
       addconf.push(
         "ZMKFILE = #{zmkfile}\n",
         "ZIMPLIB = #{zimplib}\n",
+        "ZOPTS = #{zopts.join(' ')}\n",
         "$(TARGET_SO): $(ZIMPLIB)\n",
         "$(ZIMPLIB):\n",
-        "#{zmk} $@\n",
+        "#{zmk} $(ZOPTS) $@\n",
         "install-so: $(topdir)/#{dll}",
         "$(topdir)/#{dll}: $(ZIMPLIB)\n",
         "\t$(Q) $(COPY) #{dll} $(@D)\n",

ext/zlib/extlibs

@@ -5,3 +5,4 @@ https://zlib.net/$(pkg).tar.gz \
   md5:1c9f62f0778697a09d36121ead88e08e \
   sha512:73fd3fff4adeccd4894084c15ddac89890cd10ef105dd5e1835e1e9bbb6a49ff229713bd197d203edfa17c2727700fce65a2a235f07568212d820dca88b528ae \
   #
+	win32/$(pkg)-mswin.patch -p0

ext/zlib/win32/zlib-1.2.11-mswin.patch

@@ -0,0 +1,95 @@
+diff -ru zlib-1.2.11/gzread.c zlib-1.2.11/gzread.c
+--- zlib-1.2.11/gzread.c	2016-12-31 23:37:10.000000000 +0900
++++ zlib-1.2.11/gzread.c	2020-11-23 19:35:00.550987184 +0900
+@@ -316,7 +316,7 @@
+         /* set n to the maximum amount of len that fits in an unsigned int */
+         n = -1;
+         if (n > len)
+-            n = len;
++            n = (unsigned)len;
+ 
+         /* first just try copying data from the output buffer */
+         if (state->x.have) {
+@@ -397,7 +397,7 @@
+     }
+ 
+     /* read len or fewer bytes to buf */
+-    len = gz_read(state, buf, len);
++    len = (unsigned)gz_read(state, buf, len);
+ 
+     /* check for an error */
+     if (len == 0 && state->err != Z_OK && state->err != Z_BUF_ERROR)
+@@ -469,7 +469,7 @@
+     }
+ 
+     /* nothing there -- try gz_read() */
+-    ret = gz_read(state, buf, 1);
++    ret = (int)gz_read(state, buf, 1);
+     return ret < 1 ? -1 : buf[0];
+ }
+ 
+diff -ru zlib-1.2.11/gzwrite.c zlib-1.2.11/gzwrite.c
+--- zlib-1.2.11/gzwrite.c	2017-01-15 09:29:40.000000000 +0900
++++ zlib-1.2.11/gzwrite.c	2020-11-23 19:35:41.530494030 +0900
+@@ -209,7 +209,7 @@
+                               state->in);
+             copy = state->size - have;
+             if (copy > len)
+-                copy = len;
++                copy = (unsigned)len;
+             memcpy(state->in + have, buf, copy);
+             state->strm.avail_in += copy;
+             state->x.pos += copy;
+@@ -229,7 +229,7 @@
+         do {
+             unsigned n = (unsigned)-1;
+             if (n > len)
+-                n = len;
++                n = (unsigned)len;
+             state->strm.avail_in = n;
+             state->x.pos += n;
+             if (gz_comp(state, Z_NO_FLUSH) == -1)
+@@ -368,7 +368,7 @@
+ 
+     /* write string */
+     len = strlen(str);
+-    ret = gz_write(state, str, len);
++    ret = (int)gz_write(state, str, len);
+     return ret == 0 && len != 0 ? -1 : ret;
+ }
+ 
+diff -ru zlib-1.2.11/win32/Makefile.msc zlib-1.2.11/win32/Makefile.msc
+--- zlib-1.2.11/win32/Makefile.msc	2017-01-15 09:07:08.000000000 +0900
++++ zlib-1.2.11/win32/Makefile.msc	2020-11-23 22:37:19.746500208 +0900
+@@ -37,6 +37,22 @@
+        gzwrite.obj infback.obj inflate.obj inftrees.obj inffast.obj trees.obj uncompr.obj zutil.obj
+ OBJA =
+ 
++!ifdef USE_ASM
++LOC = -DASMV -DASMINF
++!if "$(ARCH)" == "i386"
++OBJA = inffas32.obj match686.obj
++!else if "$(ARCH)" == "x64"
++AS = ml64
++LOC = $(LOC) -I.
++OBJA = inffasx64.obj gvmat64.obj inffas8664.obj
++!endif
++!endif
++
++!if "$(ARCH)" == "x64"
++ZBASE = 0x5A4C000000
++!else
++ZBASE = 0x5A4C0000
++!endif
+ 
+ # targets
+ all: $(STATICLIB) $(SHAREDLIB) $(IMPLIB) \
+@@ -49,7 +65,7 @@
+ 
+ $(SHAREDLIB): $(TOP)/win32/zlib.def $(OBJS) $(OBJA) zlib1.res
+ 	$(LD) $(LDFLAGS) -def:$(TOP)/win32/zlib.def -dll -implib:$(IMPLIB) \
+-	  -out:$@ -base:0x5A4C0000 $(OBJS) $(OBJA) zlib1.res
++	  -out:$@ -base:$(ZBASE) $(OBJS) $(OBJA) zlib1.res
+ 	if exist $@.manifest \
+ 	  mt -nologo -manifest $@.manifest -outputresource:$@;2
+