sarg FTBFS in impish

sarg currently FTBFS in impish:

...
/usr/bin/ld: readlog_common.o:./include/conf.h:314: multiple definition of `code2'; util.o:./include/conf.h:314: first defined here
/usr/bin/ld: readlog_common.o:./include/conf.h:313: multiple definition of `code'; util.o:./include/conf.h:313: first defined here
/usr/bin/ld: readlog_common.o:./include/conf.h:312: multiple definition of `period'; util.o:./include/conf.h:312: first defined here
/usr/bin/ld: readlog_common.o:./include/conf.h:311: multiple definition of `outdirname'; util.o:./include/conf.h:311: first defined here
/usr/bin/ld: readlog_common.o:./include/conf.h:310: multiple definition of `outdir'; util.o:./include/conf.h:310: first defined here
collect2: error: ld returned 1 exit status
make[1]: *** [Makefile:78: sarg] Error 1
make[1]: Leaving directory '/<<PKGBUILDDIR>>'
dh_auto_build: error: make -j1 returned exit code 2
make: *** [debian/rules:17: build] Error 25

The full build log can be found here:

https://launchpadlibrarian.net/544878407/buildlog_ubuntu-impish-amd64.sarg_2.4.0-1ubuntu3_BUILDING.txt.gz

The failure happens because sarg:

1) *A lot* of the variable declarations in the source code happen inside the include/conf.h file. This is a very bad practice.

2) There is no proper use of "extern" in the source code, so all the variables declared in the header file above get re-declared every time the header is included. It's a mess.

Upstream will probably need to re-engineer the code in a massive way, which is not feasible/recommended on our side, so I came up with an ugly but functional hack that fixes the FTBFS without changing much. I will post the patch soon.

FWIW, sarg is one of the reverse dependencies of OpenLDAP, and is blocking the transition to OpenLDAP 2.5.5.