diff --git a/test/tz_test/validate.cpp b/test/tz_test/validate.cpp
index 5a7ee08..44d9036 100644
--- a/test/tz_test/validate.cpp
+++ b/test/tz_test/validate.cpp
@@ -101,14 +101,14 @@ tzmain()
     {
         std::cout << name << '\n';
         auto z = locate_zone(name);
-        auto begin = sys_days(jan/1/year::min()) + 0s;
-        auto end   = sys_days(jan/1/2035) + 0s;
+        auto begin = sys_days(jan/1/year::min()) + seconds{0};
+        auto end   = sys_days(jan/1/2035) + seconds{0};
         auto info = z->get_info(begin);
         std::cout << "Initially:           ";
-        if (info.offset >= 0s)
+        if (info.offset >= seconds{0})
             std::cout << '+';
         std::cout << make_time(info.offset);
-        if (info.save == 0min)
+        if (info.save == minutes{0})
             std::cout << " standard ";
         else
             std::cout << " daylight ";
@@ -128,10 +128,10 @@ tzmain()
             auto ymd = year_month_day(dp);
             auto time = make_time(begin - dp);
             std::cout << ymd << ' ' << time << "Z ";
-            if (info.offset >= 0s)
+            if (info.offset >= seconds{0})
                 std::cout << '+';
             std::cout << make_time(info.offset);
-            if (info.save == 0min)
+            if (info.save == minutes{0})
                 std::cout << " standard ";
             else
                 std::cout << " daylight ";
diff --git a/tz.cpp b/tz.cpp
index b120bc3..21adb24 100644
--- a/tz.cpp
+++ b/tz.cpp
@@ -126,7 +126,7 @@ CONSTDATA auto max_day = date::dec/31;
 
 namespace detail
 {
-class undocumented {explicit undocumented() = default;};
+struct undocumented {explicit undocumented() = default;};
 }
 
 #ifndef _MSC_VER
@@ -460,7 +460,6 @@ load_timezone_mappings_from_csv_file(const std::string& input_path)
         sis.clear();
         sis.str(linebuf);
 
-        char ch;
         read_field_quote();
         std::getline(sis, zm.other, '\"');
         read_field_delim();
diff --git a/tz.h b/tz.h
index 9b9e4b7..254a68d 100644
--- a/tz.h
+++ b/tz.h
@@ -95,6 +95,7 @@ static_assert(HAS_REMOTE_API == 0 ? AUTO_DOWNLOAD == 0 : true,
 #  include <memory>
 #  include <mutex>
 #endif
+#include <time.h>
 
 namespace date
 {
@@ -103,7 +104,7 @@ enum class choose {earliest, latest};
 
 namespace detail
 {
-    class undocumented;
+    struct undocumented;
 }
 
 class nonexistent_local_time
@@ -1431,10 +1432,10 @@ parse(std::basic_istream<CharT, Traits>& is,
                 f.get(is, 0, is, err, &tm, b, e);
             if ((err & ios_base::failbit) == 0)
             {
-#ifndef _MSC_VER
-                auto tt = timegm(&tm);
-#else
+#if _WIN32
                 auto tt = _mkgmtime(&tm);
+#else
+                auto tt = timegm(&tm);
 #endif
                 tp = floor<Duration>(system_clock::from_time_t(tt) + subseconds);
                 abbrev = std::move(temp_abbrev);