fixup 2b0841b0: forgot to add new file

src/support/mute_warning.h

@@ -0,0 +1,43 @@
+// -*- C++ -*-
+/**
+ * \file mute_warning.h
+ * This file is part of LyX, the document processor.
+ * Licence details can be found in the file COPYING.
+ *
+ * \author Lars Gullik Bjønnes
+ * \author Georg Baum
+ *
+ * Full author contact details are available in file CREDITS.
+ */
+
+#ifndef LYX_MUTE_WARNING_H
+#define LYX_MUTE_WARNING_H
+
+#if defined(__GNUC__) && !defined(__clang__)
+/* This macro can be used to stipulate that a given GCC warning is not
+ * relevant in a given block.
+ *
+ * The -Wpragmas bit takes care of the case where -W<warn> is not implemented
+ *
+ * The idea for PRAGMA_IGNORE has been stolen from
+ * https://stackoverflow.com/questions/45762357/how-to-concatenate-strings-in-the-arguments-of-pragma#comment124444258_45783809
+ * The difficulty is to put the <warn> value inside nested quotes; it is done
+ * using nested macros.
+ */
+#  define PRAGMA_IGNORE(x) PRAGMA_IGNORE_1(-W##x)
+#  define PRAGMA_IGNORE_1(x) PRAGMA_IGNORE_2(#x)
+#  define PRAGMA_IGNORE_2(x) PRAGMA_IGNORE_3(GCC diagnostic ignored x)
+#  define PRAGMA_IGNORE_3(x) _Pragma(#x)
+#  define LYX_BEGIN_MUTE_GCC_WARNING(warn)		\
+  _Pragma("GCC diagnostic push") \
+  _Pragma("GCC diagnostic ignored \"-Wpragmas\"") \
+  PRAGMA_IGNORE(warn)
+#  define LYX_END_MUTE_GCC_WARNING \
+  _Pragma("GCC diagnostic pop")
+#else
+#  define LYX_BEGIN_MUTE_GCC_WARNING(warn)
+#  define LYX_END_MUTE_GCC_WARNING
+#endif
+
+
+#endif