Move get_os_major_version() to wsutil and rename it to get_windows_major_version().

It's Windows-specific, so name it appropriately.

Change-Id: Ic518cbfabebf95757f6b308a4d547a6cabed6a5e
Reviewed-on: https://code.wireshark.org/review/2528
Reviewed-by: Guy Harris <guy@alum.mit.edu>

tshark.c

@@ -66,6 +66,7 @@
 #include <wsutil/filesystem.h>
 #include <wsutil/report_err.h>
 #include <wsutil/copyright_info.h>
+#include <wsutil/os_version_info.h>
 
 #include "globals.h"
 #include <epan/timestamp.h>
@@ -895,7 +896,7 @@ check_capture_privs(void) {
 #ifdef _WIN32
   load_wpcap();
   /* Warn the user if npf.sys isn't loaded. */
-  if (!npf_sys_is_running() && get_os_major_version() >= 6) {
+  if (!npf_sys_is_running() && get_windows_major_version() >= 6) {
     fprintf(stderr, "The NPF driver isn't running.  You may have trouble "
       "capturing or\nlisting interfaces.\n");
   }

ui/gtk/main.c

@@ -63,6 +63,7 @@
 #include <wsutil/report_err.h>
 #include <wsutil/u3.h>
 #include <wsutil/copyright_info.h>
+#include <wsutil/os_version_info.h>
 
 #include <wiretap/merge.h>
 
@@ -2100,7 +2101,7 @@ check_and_warn_user_startup(gchar *cf_name _U_)
 
 #ifdef _WIN32
     /* Warn the user if npf.sys isn't loaded. */
-    if (!get_stdin_capture() && !cf_name && !npf_sys_is_running() && recent.privs_warn_if_no_npf && get_os_major_version() >= 6) {
+    if (!get_stdin_capture() && !cf_name && !npf_sys_is_running() && recent.privs_warn_if_no_npf && get_windows_major_version() >= 6) {
         priv_warning_dialog = simple_dialog(ESD_TYPE_WARN, ESD_BTN_OK,
         "The NPF driver isn't running.  You may have trouble\n"
         "capturing or listing interfaces.");

version_info.c

@@ -40,10 +40,6 @@
 
 #include "version.h"
 
-#ifdef _WIN32
-#include <windows.h>
-#endif
-
 #ifdef HAVE_LIBCAP
 # include <sys/capability.h>
 #endif
@@ -219,23 +215,6 @@ get_runtime_version_info(GString *str, void (*additional_info)(GString *))
 	end_string(str);
 }
 
-#if defined(_WIN32)
-/*
- * Get the major OS version.
- */
-/* XXX - Should this return the minor version as well, e.g. 0x00050002? */
-guint32
-get_os_major_version()
-{
-	OSVERSIONINFO info;
-	info.dwOSVersionInfoSize = sizeof info;
-	if (GetVersionEx(&info)) {
-		return info.dwMajorVersion;
-	}
-	return 0;
-}
-#endif
-
 /*
  * Editor modelines
  *

version_info.h

@@ -56,13 +56,6 @@ void get_compiled_version_info(GString *str,
 void get_runtime_version_info(GString *str,
     void (*additional_info)(GString *));
 
-#if defined(_WIN32)
-/*
- * Get the major OS version.
- */
-guint32 get_os_major_version();
-#endif
-
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */

wsutil/os_version_info.c

@@ -476,3 +476,27 @@ get_os_version_info(GString *str)
 	g_string_append(str, "an unknown OS");
 #endif
 }
+
+#if defined(_WIN32)
+/*
+ * Get the Windows major OS version.
+ *
+ * XXX - Should this return the minor version as well, e.g. 0x00050002?
+ *
+ * XXX - I think Microsoft have now stuck it at 6 forever, so it really
+ * distinguishes, on the versions of Windows we currently support and
+ * future Windows versions between Windows 2000/XP (major version 5) and
+ * everything after it (major version 6).
+ */
+guint32
+get_windows_major_version(void)
+{
+	OSVERSIONINFO info;
+
+	info.dwOSVersionInfoSize = sizeof info;
+	if (GetVersionEx(&info)) {
+		return info.dwMajorVersion;
+	}
+	return 0;
+}
+#endif

wsutil/os_version_info.h

@@ -34,6 +34,13 @@ extern "C" {
  */
 WS_DLL_PUBLIC void get_os_version_info(GString *str);
 
+#ifdef _WIN32
+/*
+ * Get the Windows major OS version.
+ */
+WS_DLL_PUBLIC guint32 get_windows_major_version(void);
+#endif
+
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */