coinmp: disable "glpk", whatever that is

On Fedora 31, this happens in CppunitTest_sccomp_solver:

- loading component library <file:///work/lo/master/instdir/program/libsolverlo.so> failed

> nm -D instdir/program/libCbcSolver.so.3 | grep cbc_glp_prob
                 U cbc_glp_prob

> grep -r COIN_HAS_GLPK workdir/UnpackedTarball/coinmp | grep config.h
workdir/UnpackedTarball/coinmp/Osi/src/Osi/config.h:/* #undef COIN_HAS_GLPK */
workdir/UnpackedTarball/coinmp/Clp/src/config.h.in:#undef COIN_HAS_GLPK
workdir/UnpackedTarball/coinmp/Cbc/src/config.h:#define COIN_HAS_GLPK 1
workdir/UnpackedTarball/coinmp/CoinUtils/src/config.h.in:#undef COIN_HAS_GLPK

Somehow 2 different configures in coinmp got different ideas about
whether something named "glpk" is available.... no idea what that is,
it looks like there's a "glpk-devel" package installed on the system,
and i doubt that a dependency on that would be desirable.

Change-Id: Ief01b6aedc692197c1a8fd6351aef4281e530e70
Reviewed-on: https://gerrit.libreoffice.org/81863
Tested-by: Jenkins
Reviewed-by: Michael Stahl <michael.stahl@cib.de>

external/coinmp/ExternalProject_coinmp.mk

@@ -33,6 +33,7 @@ $(call gb_ExternalProject_get_state_target,coinmp,build) :
 			$(if $(DISABLE_DYNLOADING),--disable-shared) \
 			--disable-bzlib \
 			$(if $(filter MACOSX,$(OS)),--prefix=/@.__________________________________________________OOO) \
+			--without-glpk \
 			--enable-dependency-linking F77=unavailable \
 			$(if $(filter LINUX,$(OS)), \
 				'LDFLAGS=-Wl$(COMMA)-z$(COMMA)origin \