[LyX/master] Yet another deprecation fix (this is the last one I am aware of)

[Juergen Spitzmueller]

commit 9f92fc92bdd41c367b0975454a01c15403d51a60
Author: Juergen Spitzmueller <spitz at lyx.org>
Date:   Fri Mar 12 12:14:42 2021 +0100

    Yet another deprecation fix (this is the last one I am aware of)
---
 src/support/Systemcall.cpp |   17 +++++++++++++++++
 1 files changed, 17 insertions(+), 0 deletions(-)

diff --git a/src/support/Systemcall.cpp b/src/support/Systemcall.cpp
index 815223d..00adbf8 100644
--- a/src/support/Systemcall.cpp
+++ b/src/support/Systemcall.cpp
@@ -368,6 +368,15 @@ void SystemcallPrivate::startProcess(QString const & cmd, string const & path,
                                      string const & lpath, bool detached)
 {
 	cmd_ = cmd;
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 15, 0))
+	// FIXME pass command and arguments separated in the first place
+	QStringList arguments = QProcess::splitCommand(toqstr(latexEnvCmdPrefix(path, lpath)) + cmd_);
+	QString command = (arguments.empty()) ? QString() : arguments.first();
+	if (arguments.size() == 1)
+		arguments.clear();
+	else if (!arguments.empty())
+		arguments.removeFirst();
+#endif
 	if (detached) {
 		state = SystemcallPrivate::Running;
 #ifdef Q_OS_WIN32
@@ -379,7 +388,11 @@ void SystemcallPrivate::startProcess(QString const & cmd, string const & path,
 		if (err_file_.empty())
 			process_->setStandardErrorFile(QProcess::nullDevice());
 #endif
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 15, 0))
+		if (!QProcess::startDetached(command, arguments)) {
+#else
 		if (!QProcess::startDetached(toqstr(latexEnvCmdPrefix(path, lpath)) + cmd_)) {
+#endif
 			state = SystemcallPrivate::Error;
 			return;
 		}
@@ -387,7 +400,11 @@ void SystemcallPrivate::startProcess(QString const & cmd, string const & path,
 		delete released;
 	} else if (process_) {
 		state = SystemcallPrivate::Starting;
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 15, 0))
+		process_->start(command, arguments);
+#else
 		process_->start(toqstr(latexEnvCmdPrefix(path, lpath)) + cmd_);
+#endif
 	}
 }