Append current typesetting tool's path to $PATH on Mac OS X (fixes #861…

…, fixes #897)

This way, programs in the same directory as the typesetting tool can be
found, even though .bash_profile etc. are not parsed when running
TeXworks from the Finder.

src/Engine.cpp

@@ -131,6 +131,22 @@ QProcess * Engine::run(const QFileInfo & input, QObject * parent /* = nullptr */
 	env.insert(QStringLiteral("MIKTEX_EDITOR"), QStringLiteral("%1 --position=%l \"%f\"").arg(QCoreApplication::applicationFilePath()));
 #endif
 
+#if defined(Q_OS_DARWIN)
+	// On Mac OS X, append the path to the typesetting tool to the PATH
+	// environment variable.
+	// In recent versions of Mac OS X and Qt, GUI applications (like Tw) get
+	// different values for PATH than console applications (because .bashrc etc.
+	// don't get parsed). Typesetting tools still run correctly (as they are
+	// invoked with a full path), but if they in turn try to run other tools
+	// (like epstopdf) without full path, the process will fail.
+	// Appending the path to the typesetting tool to PATH acts as a fallback and
+	// implicitly assumes that the tool itself and all tools it relies on are in
+	// the same (standard) location.
+	QStringList envPaths = env.value(QStringLiteral("PATH")).split(QStringLiteral(PATH_LIST_SEP));
+	envPaths.append(QFileInfo(exeFilePath).dir().absolutePath());
+	env.insert(QStringLiteral("PATH"), envPaths.join(QStringLiteral(PATH_LIST_SEP)));
+#endif
+
 	QStringList args = arguments();
 
 	// for old MikTeX versions: delete $synctexoption if it causes an error