Windows XP target support for MSVC >= 2012

To enable windows xp support, we must do two things:
1. linker flag must be /SUBSYSTEM:CONSOLE,5.01 or
   /SUBSYSTEM:WINDOWS,5.01. For x64, the version is 5.02.
2. Do not use Windows Kit 8. Win SDK v7.1A is recommended. Prepend the
   right include paths and lib paths to INCLUDE and LIB before
   building.

The Windows XP target support is enabled by passing "-target xp" to
configure.

Task-number: QTBUG-29939

Change-Id: I84c8439606cc2a9d27d64947702846faa4f1e4a2
Reviewed-by: Lucas Wang <wbsecg1@gmail.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>

1 files changed, 28 insertions, 1 deletions

diff --git a/tools/configure/configureapp.cpp b/tools/configure/configureapp.cpp
index 176fe3092f..49c7fc9618 100644
--- a/tools/configure/configureapp.cpp
+++ b/tools/configure/configureapp.cpp
@@ -482,7 +482,18 @@ void Configure::parseCmdLine()
         else if (configCmdLine.at(i) == "-force-asserts") {
             dictionary[ "FORCE_ASSERTS" ] = "yes";
         }
-
+        else if (configCmdLine.at(i) == "-target") {
+            ++i;
+            if (i == argCount)
+                break;
+            const QString option = configCmdLine.at(i);
+            if (option != "xp") {
+                cout << "ERROR: invalid argument for -target option" << endl;
+                dictionary["DONE"] = "error";
+                return;
+            }
+            dictionary["TARGET_OS"] = option;
+        }
         else if (configCmdLine.at(i) == "-platform") {
             ++i;
             if (i == argCount)
@@ -1817,6 +1828,10 @@ bool Configure::displayHelp()
         desc(                   "-platform <spec>",     "The operating system and compiler you are building on.\n(default %QMAKESPEC%)\n");
         desc(                   "-xplatform <spec>",    "The operating system and compiler you are cross compiling to.\n");
         desc(                   "",                     "See the README file for a list of supported operating systems and compilers.\n", false, ' ');
+
+        desc("TARGET_OS", "*", "-target",               "Set target OS version. Currently the only valid value is 'xp' for targeting Windows XP.\n"
+                                                        "MSVC >= 2012 targets Windows Vista by default.\n");
+
         desc(                   "-sysroot <dir>",       "Sets <dir> as the target compiler's and qmake's sysroot and also sets pkg-config paths.");
         desc(                   "-no-gcc-sysroot",      "When using -sysroot, it disables the passing of --sysroot to the compiler.\n");
 
@@ -2497,6 +2512,12 @@ bool Configure::verifyConfiguration()
              << "files such as headers and libraries." << endl;
         prompt = true;
     }
+#if WINVER > 0x0601
+    if (dictionary["TARGET_OS"] == "xp") {
+        cout << "WARNING: Cannot use Windows Kit 8 to build Qt for Windows XP.\n"
+                "WARNING: Windows SDK v7.1A is recommended.\n";
+    }
+#endif
 
     if (dictionary["DIRECT2D"] == "yes" && !checkAvailability("DIRECT2D")) {
         cout << "WARNING: To be able to build the Direct2D platform plugin you will" << endl
@@ -3331,6 +3352,10 @@ void Configure::generateQConfigPri()
                          << "}" << endl;
         }
 
+        const QString targetOS = dictionary.value("TARGET_OS");
+        if (!targetOS.isEmpty())
+            configStream << "QMAKE_TARGET_OS = " << targetOS << endl;
+
         if (!dictionary["QMAKE_RPATHDIR"].isEmpty())
             configStream << "QMAKE_RPATHDIR += " << formatPath(dictionary["QMAKE_RPATHDIR"]) << endl;
 
@@ -3574,6 +3599,8 @@ void Configure::displayConfig()
         sout << "QMAKESPEC..................." << dictionary[ "XQMAKESPEC" ] << " (" << dictionary["QMAKESPEC_FROM"] << ")" << endl;
     else
         sout << "QMAKESPEC..................." << dictionary[ "QMAKESPEC" ] << " (" << dictionary["QMAKESPEC_FROM"] << ")" << endl;
+    if (!dictionary["TARGET_OS"].isEmpty())
+        sout << "Target OS..................." << dictionary["TARGET_OS"] << endl;
     sout << "Architecture................" << dictionary["QT_ARCH"]
          << ", features:" << dictionary["QT_CPU_FEATURES"] << endl;
     sout << "Host Architecture..........." << dictionary["QT_HOST_ARCH"]