rng-tools: ignore incompatible-pointer-types errors for now

* causes libargp test to fail:

http://errors.yoctoproject.org/Errors/Details/766951/



| configure: error: in '/OE/build/luneos-styhead/tmp-glibc/work/qemux86_64-webos-linux/rng-tools/6.16/build':
| configure: error: libargp disabled and libc does not have argp

config.log shows:

configure:8424: x86_64-webos-linux-gcc  -m64 -march=nehalem -mtune=generic -mfpmath=sse -msse4.2 --sysroot=/OE/build/luneos-styhead/tmp-glibc/work/qemux86_64-webos-linux/rng-tools/6.16/recipe-sysroot -o conftest  -O2 -pipe -g -feliminate-unused-debug-types -fcanon-prefix-map  -fmacro-prefix-map=/OE/build/luneos-styhead/tmp-glibc/work/qemux86_64-webos-linux/rng-tools/6.16/git=/usr/src/debug/rng-tools/6.16  -fdebug-prefix-map=/OE/build/luneos-styhead/tmp-glibc/work/qemux86_64-webos-linux/rng-tools/6.16/git=/usr/src/debug/rng-tools/6.16  -fmacro-prefix-map=/OE/build/luneos-styhead/tmp-glibc/work/qemux86_64-webos-linux/rng-tools/6.16/build=/usr/src/debug/rng-tools/6.16  -fdebug-prefix-map=/OE/build/luneos-styhead/tmp-glibc/work/qemux86_64-webos-linux/rng-tools/6.16/build=/usr/src/debug/rng-tools/6.16  -fdebug-prefix-map=/OE/build/luneos-styhead/tmp-glibc/work/qemux86_64-webos-linux/rng-tools/6.16/recipe-sysroot=  -fmacro-prefix-map=/OE/build/luneos-styhead/tmp-glibc/work/qemux86_64-webos-linux/rng-tools/6.16/recipe-sysroot=  -fdebug-prefix-map=/OE/build/luneos-styhead/tmp-glibc/work/qemux86_64-webos-linux/rng-tools/6.16/recipe-sysroot-native=   -DJENT_CONF_ENABLE_INTERNAL_TIMER   -Wl,-O1 -Wl,--hash-style=gnu -Wl,--as-needed -fcanon-prefix-map  -fmacro-prefix-map=/OE/build/luneos-styhead/tmp-glibc/work/qemux86_64-webos-linux/rng-tools/6.16/git=/usr/src/debug/rng-tools/6.16  -fdebug-prefix-map=/OE/build/luneos-styhead/tmp-glibc/work/qemux86_64-webos-linux/rng-tools/6.16/git=/usr/src/debug/rng-tools/6.16  -fmacro-prefix-map=/OE/build/luneos-styhead/tmp-glibc/work/qemux86_64-webos-linux/rng-tools/6.16/build=/usr/src/debug/rng-tools/6.16  -fdebug-prefix-map=/OE/build/luneos-styhead/tmp-glibc/work/qemux86_64-webos-linux/rng-tools/6.16/build=/usr/src/debug/rng-tools/6.16  -fdebug-prefix-map=/OE/build/luneos-styhead/tmp-glibc/work/qemux86_64-webos-linux/rng-tools/6.16/recipe-sysroot=  -fmacro-prefix-map=/OE/build/luneos-styhead/tmp-glibc/work/qemux86_64-webos-linux/rng-tools/6.16/recipe-sysroot=  -fdebug-prefix-map=/OE/build/luneos-styhead/tmp-glibc/work/qemux86_64-webos-linux/rng-tools/6.16/recipe-sysroot-native=  conftest.c -ljitterentropy  >&5
conftest.c: In function 'main':
conftest.c:51:52: error: passing argument 3 of 'argp_parse' from incompatible pointer type [-Wincompatible-pointer-types]
   51 | int argc=1; char *argv={"test"}; argp_parse(0,argc,argv,0,0,0); return 0;
      |                                                    ^~~~
      |                                                    |
      |                                                    char *
In file included from conftest.c:47:
/OE/build/luneos-styhead/tmp-glibc/work/qemux86_64-webos-linux/rng-tools/6.16/recipe-sysroot/usr/include/argp.h:371:58: note: expected 'char ** restrict' but argument is of type 'char *'
  371 |                            int __argc, char **__restrict __argv,
      |                                        ~~~~~~~~~~~~~~~~~~^~~~~~

Signed-off-by: Martin Jansa <martin.jansa@gmail.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>