Makefile: enable -Werror=implicit-int and -Werror=strict-prototypes by default

Sergei Trofimovich · michal42 · commit 80970472179a · 2013-10-23T16:36:57.000+02:00
The common error found in forward-ported/backported patches is missing
headers.  One recent example (files and function names are mangled):

    void foo(){}
    EXPORT_SYMBOL(foo);

gave only warning

    foo.c:12345678:5: warning: function declaration isn't a prototype [-Wstrict-prototypes]
    void foo(){}
         ^

    foo.c:12345679:5: warning: data definition has no type or storage class [enabled by default]
    EXPORT_SYMBOL(foo);
    foo.c:12345679:5: warning: type defaults to 'int' in declaration of 'EXORT_SYMBOL' [-Werror=implicit-int]

Now it's a fatal error. Tested on x86_64 allyesconfig.

[akpm@linux-foundation.org: fix typos in comments]
Signed-off-by: Sergei Trofimovich &lt;slyfox@gentoo.org&gt;
Cc: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Michal Marek &lt;mmarek@suse.cz&gt;
diff --git a/Makefile b/Makefile
@@ -659,6 +659,12 @@ KBUILD_CFLAGS	+= $(call cc-option,-fno-strict-overflow)
 # conserve stack if available
 KBUILD_CFLAGS   += $(call cc-option,-fconserve-stack)
 
+# disallow errors like 'EXPORT_GPL(foo);' with missing header
+KBUILD_CFLAGS   += $(call cc-option,-Werror=implicit-int)
+
+# require functions to have arguments in prototypes, not empty 'int foo()'
+KBUILD_CFLAGS   += $(call cc-option,-Werror=strict-prototypes)
+
 # use the deterministic mode of AR if available
 KBUILD_ARFLAGS := $(call ar-option,D)
 
