TT#70472 Disable unsafe signal handlers

We should not be calling async-signal-unsafe functions from within
signal handlers. This is in general bad on a non-threaded program,
but probably way worse with threading enabled.

Change-Id: I2931ce394f703b420c491438136029a670c83207
(cherry picked from commit 3cd4b897a2)

debian/rules

@@ -121,6 +121,9 @@ LD_EXTRA_OPTS := $(shell dpkg-buildflags --get LDFLAGS)
 # https://wiki.debian.org/ReproducibleBuilds/
 CC_EXTRA_OPTS += -DVERSION_NODATE
 
+# Disable unsafe signal handlers
+CC_EXTRA_OPTS += -DNO_SIG_DEBUG
+
 # Fix for UDP buffer issue when TLS is enabled
 CC_EXTRA_OPTS += -pthread -DKSR_PTHREAD_MUTEX_SHARED
 LD_EXTRA_OPTS += -pthread -rdynamic -ldl -Wl,-Bsymbolic-functions