diff --git a/ext/nio4r/bytebuffer.c b/ext/nio4r/bytebuffer.c
index c23b953..bd9bf03 100644
--- a/ext/nio4r/bytebuffer.c
+++ b/ext/nio4r/bytebuffer.c
@@ -124,10 +124,11 @@ static VALUE NIO_ByteBuffer_get_position(VALUE self)
 
 static VALUE NIO_ByteBuffer_set_position(VALUE self, VALUE new_position)
 {
+    int pos;
     struct NIO_ByteBuffer *buffer;
     Data_Get_Struct(self, struct NIO_ByteBuffer, buffer);
 
-    int pos = NUM2INT(new_position);
+    pos = NUM2INT(new_position);
 
     if(pos < 0) {
         rb_raise(rb_eArgError, "negative position given");
@@ -156,10 +157,11 @@ static VALUE NIO_ByteBuffer_get_limit(VALUE self)
 
 static VALUE NIO_ByteBuffer_set_limit(VALUE self, VALUE new_limit)
 {
+    int lim;
     struct NIO_ByteBuffer *buffer;
     Data_Get_Struct(self, struct NIO_ByteBuffer, buffer);
 
-    int lim = NUM2INT(new_limit);
+    lim = NUM2INT(new_limit);
 
     if(lim < 0) {
         rb_raise(rb_eArgError, "negative limit given");
@@ -237,10 +239,11 @@ static VALUE NIO_ByteBuffer_get(int argc, VALUE *argv, VALUE self)
 
 static VALUE NIO_ByteBuffer_fetch(VALUE self, VALUE index)
 {
+    int i;
     struct NIO_ByteBuffer *buffer;
     Data_Get_Struct(self, struct NIO_ByteBuffer, buffer);
 
-    int i = NUM2INT(index);
+    i = NUM2INT(index);
 
     if(i < 0) {
         rb_raise(rb_eArgError, "negative index given");
@@ -255,10 +258,11 @@ static VALUE NIO_ByteBuffer_fetch(VALUE self, VALUE index)
 
 static VALUE NIO_ByteBuffer_put(VALUE self, VALUE string)
 {
+    long length;
     struct NIO_ByteBuffer *buffer;
     Data_Get_Struct(self, struct NIO_ByteBuffer, buffer);
 
-    long length = RSTRING_LEN(string);
+    length = RSTRING_LEN(string);
 
     if(length > buffer->limit - buffer->position) {
         rb_raise(cNIO_ByteBuffer_OverflowError, "buffer is full");
diff --git a/ext/nio4r/extconf.rb b/ext/nio4r/extconf.rb
index a763719..1df63a7 100644
--- a/ext/nio4r/extconf.rb
+++ b/ext/nio4r/extconf.rb
@@ -18,14 +18,14 @@
 
 $defs << "-DHAVE_SYS_RESOURCE_H" if have_header("sys/resource.h")
 
-CONFIG["optflags"] << " -fno-strict-aliasing"
+CONFIG["optflags"] << " -fno-strict-aliasing" unless RUBY_PLATFORM =~ /mswin/
 
 dir_config "nio4r_ext"
 create_makefile "nio4r_ext"
 
 # win32 needs to link in "just the right order" for some reason or
 # ioctlsocket will be mapped to an [inverted] ruby specific version.
-if RUBY_PLATFORM =~ /mingw|win32/
+if RUBY_PLATFORM =~ /mingw|mswin/
   makefile_contents = File.read "Makefile"
 
   makefile_contents.gsub! "DLDFLAGS = ", "DLDFLAGS = -export-all "