NuttX generates the app main name from Kconfig symbol
xxxx_PROGNAME. The documentation was defining manually
the entry point as custom_hello(int char, char *argv[])
and pointing CONFIG_INIT_ENTRYPOINT="custom_hello".
The right thing to do is creating the application entry
point as "int main(int char, char *argv[])" and the build
system will add "_main" to the PROGNAME.
Signed-off-by: Alan C. Assis <acassis@gmail.com>
