Fix build with CURL_DEBUG enabled

lib/checksrc.pl is run when CURL_DEBUG is enabled.
The build failed due to the long line in patched lib/url.c.

./url.c:593:82: warning: Longer than 79 columns (LONGLINE)

data->set.no_signal = TRUE; /* different handling of signals and threads */

checksrc: 0 errors and 1 warnings
checksrc: 0 errors and 5 warnings suppressed
gmake[3]: *** [Makefile:3935: checksrc] Error 5

MFH: 2018Q1