[host] windows: read ProductName from registry if possible

For Windows 10, it so happens that the major.minor is 10.0. This is not
usually a given, e.g. on Windows 7 where it would read 6.1, on
Windows 8 it would read 6.2, and on Windows 8.1 it would read 6.3.

This is obviously undesirable, so we should just read the ProductName
from registry if possible. This results in something like:

    OS Name: Windows 10 Pro for Workstations (Build: 19043)

host/platform/Windows/src/platform.c

@@ -615,6 +615,21 @@ KVMFROS os_getKVMFRType(void)
   return KVMFR_OS_WINDOWS;
 }
 
+static bool getProductName(char * buffer, DWORD bufferSize)
+{
+  LSTATUS status = RegGetValueA(HKEY_LOCAL_MACHINE,
+    "Software\\Microsoft\\Windows NT\\CurrentVersion", "ProductName",
+    RRF_RT_REG_SZ, NULL, buffer, &bufferSize);
+
+  if (status != ERROR_SUCCESS)
+  {
+    DEBUG_WINERROR("Failed to read ProductName from registry", status);
+    return false;
+  }
+
+  return true;
+}
+
 const char * os_getOSName(void)
 {
   if (app.osVersion)
@@ -624,6 +639,19 @@ const char * os_getOSName(void)
   osvi.dwOSVersionInfoSize = sizeof(osvi);
   GetVersionExA(&osvi);
 
+  char productName[1024];
+  if (getProductName(productName, sizeof(productName)))
+  {
+    alloc_sprintf(
+      &app.osVersion,
+      "%s (Build: %lu) %s",
+      productName,
+      osvi.dwBuildNumber,
+      osvi.szCSDVersion
+    );
+  }
+  else
+  {
     alloc_sprintf(
       &app.osVersion,
       "Windows %lu.%lu (Build: %lu) %s",
@@ -632,6 +660,7 @@ const char * os_getOSName(void)
       osvi.dwBuildNumber,
       osvi.szCSDVersion
     );
+  }
 
   return app.osVersion;
 }