tools: Cleanup EXTRA_WARNINGS

Use += instead of the bash syntax, as Sam Ravnborg suggests. Also, sort
the -W options alphabetically and (... keep them sorted).

Suggested-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Sam Ravnborg <sam@ravnborg.org>
Link: http://lkml.kernel.org/r/1334162178-17152-3-git-send-email-bp@amd64.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/scripts/Makefile.include

@@ -11,26 +11,26 @@ endif
 #
 # Include saner warnings here, which can catch bugs:
 #
-EXTRA_WARNINGS := -Wformat
-EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wformat-security
-EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wformat-y2k
-EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wshadow
-EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Winit-self
-EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wpacked
-EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wredundant-decls
-EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wstrict-aliasing=3
-EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wswitch-default
-EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wswitch-enum
-EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wno-system-headers
-EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wundef
-EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wwrite-strings
-EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wbad-function-cast
-EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wmissing-declarations
-EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wmissing-prototypes
-EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wnested-externs
-EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wold-style-definition
-EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wstrict-prototypes
-EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wdeclaration-after-statement
+EXTRA_WARNINGS := -Wbad-function-cast
+EXTRA_WARNINGS += -Wdeclaration-after-statement
+EXTRA_WARNINGS += -Wformat-security
+EXTRA_WARNINGS += -Wformat-y2k
+EXTRA_WARNINGS += -Winit-self
+EXTRA_WARNINGS += -Wmissing-declarations
+EXTRA_WARNINGS += -Wmissing-prototypes
+EXTRA_WARNINGS += -Wnested-externs
+EXTRA_WARNINGS += -Wno-system-headers
+EXTRA_WARNINGS += -Wold-style-definition
+EXTRA_WARNINGS += -Wpacked
+EXTRA_WARNINGS += -Wredundant-decls
+EXTRA_WARNINGS += -Wshadow
+EXTRA_WARNINGS += -Wstrict-aliasing=3
+EXTRA_WARNINGS += -Wstrict-prototypes
+EXTRA_WARNINGS += -Wswitch-default
+EXTRA_WARNINGS += -Wswitch-enum
+EXTRA_WARNINGS += -Wundef
+EXTRA_WARNINGS += -Wwrite-strings
+EXTRA_WARNINGS += -Wformat
 
 ifneq ($(findstring $(MAKEFLAGS), w),w)
 PRINT_DIR = --no-print-directory