make the extra warnings optional

Rules.mak

@@ -295,10 +295,12 @@ OPTIMIZATION+=$(call check_gcc,-funit-at-a-time,)
 
 # Add a bunch of extra pedantic annoyingly strict checks
 XWARNINGS=$(subst ",, $(strip $(WARNINGS))) -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing
+ifeq ($(EXTRA_WARNINGS),y)
 XWARNINGS+=-Wnested-externs -Wshadow -Wmissing-noreturn -Wmissing-format-attribute -Wformat=2
 XWARNINGS+=-Wmissing-prototypes -Wmissing-declarations
 # works only w/ gcc-3.4 and up, can't be checked for gcc-3.x w/ check_gcc()
 #XWARNINGS+=-Wdeclaration-after-statement
+endif
 XARCH_CFLAGS=$(subst ",, $(strip $(ARCH_CFLAGS)))
 CPU_CFLAGS=$(subst ",, $(strip $(CPU_CFLAGS-y)))
 

extra/Configs/Config.in

@@ -1450,6 +1450,12 @@ config WARNINGS
 	help
 	  Set this to the set of gcc warnings you wish to see while compiling.
 
+config EXTRA_WARNINGS
+	bool "Enable extra annoying warnings"
+	default n
+	help
+	  If you wish to build with extra warnings enabled, say Y here.
+
 config DOMULTI
 	bool "Compile all sources at once into an object"
 	default n