Reinstate DEBUG_PESSIMIZE (by Christian Ionescu-Idbohrn)

diff --git a/Config.in b/Config.in
index 3b37496..0a7edf8 100644
--- a/Config.in
+++ b/Config.in
@@ -396,6 +396,17 @@
 
 	  Most people should answer N.
 
+config DEBUG_PESSIMIZE
+	bool "Disable compiler optimizations."
+	default n
+	depends on DEBUG
+	help
+	  The compiler's optimization of source code can eliminate and reorder
+	  code, resulting in an executable that's hard to understand when
+	  stepping through it with a debugger.  This switches it off, resulting
+	  in a much bigger executable that more closely matches the source
+	  code.
+
 config WERROR
 	bool "Abort compilation on any warning"
 	default n
@@ -404,18 +415,6 @@
 
 	  Most people should answer N.
 
-# Seems to be unused
-#config DEBUG_PESSIMIZE
-#	bool "Disable compiler optimizations."
-#	default n
-#	depends on DEBUG
-#	help
-#	  The compiler's optimization of source code can eliminate and reorder
-#	  code, resulting in an executable that's hard to understand when
-#	  stepping through it with a debugger.  This switches it off, resulting
-#	  in a much bigger executable that more closely matches the source
-#	  code.
-
 choice
 	prompt "Additional debugging library"
 	default NO_DEBUG_LIB