slinky example building error

[王华源]

Hi,


  When I build slinky native example  as document,  the builder throws error


    Building target targets/sim_slinky

Compiling x509_crl.c

Error: x509_crl.c: In function 'mbedtls_x509_crl_parse':

x509_crl.c:508:5: error: this 'else' clause does not guard... 
[-Werror=misleading-indentation]

     else

     ^~~~

x509_crl.c:514:9: note: ...this statement, but the latter is misleadingly 
indented as if it is guarded by the 'else'

         if( ret == 0 )

         ^~

cc1: all warnings being treated as errors