This is workaround for Studio compiler bug 24660887.

When build with -xO4 object will miss symbol like this:

symbol .L77001888: referenced symbol not found

Not suitable for upstream.

--- plugins/profinet/Makefile.in
+++ plugins/profinet/Makefile.in
@@ -300,7 +300,7 @@
 CC = @CC@
 CCDEPMODE = @CCDEPMODE@
 CC_FOR_BUILD = @CC_FOR_BUILD@
-CFLAGS = @CFLAGS@
+CFLAGS = @CFLAGS@ -xO3
 CFLAGS_FOR_BUILD = @CFLAGS_FOR_BUILD@
 CFLAGS_SSE42 = @CFLAGS_SSE42@
 CONFIG_ARGS = @CONFIG_ARGS@