Hi

The Debian QA linters noticed that some CC flags were missing, and this
patch fixes it.  It seems the default CFLAGS for me is '-O2 -g' when
running ./configure so I dropped those since they were added twice
otherwise.  Maye -Wall should be moved to a Makefile.am AM_CFLAGS (or
something), but the attached patch seems sufficient to silences Debian's
"blhc" tool which is my main concern.

https://salsa.debian.org/debian/shepherd/-/jobs/7100765

400:CFLAGS missing (-fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -fcf-protection): 			\ gcc -O2 -g -Wall -shared -fPIC -o "etc/crash-handler.so" "etc/crash-handler.c"
400:CPPFLAGS missing (-D_FORTIFY_SOURCE=2): 			\ gcc -O2 -g -Wall -shared -fPIC -o "etc/crash-handler.so" "etc/crash-handler.c"
400:LDFLAGS missing (-Wl,-z,relro): 			\ gcc -O2 -g -Wall -shared -fPIC -o "etc/crash-handler.so" "etc/crash-handler.c"

/Simon