Add build option to enable urpmreorder solver flag

This optionally enables the urpm-style solution reordering
required to ensure the proper subset of locale and kernel packages
were being installed.

Reference: https://bugs.mageia.org/show_bug.cgi?id=18315

CMakeLists.txt

@@ -31,6 +31,7 @@ option(WITH_PYTHON_PLUGINS_LOADER "Build a special dnf5 plugin that loads Python
 option(WITH_COMPS "Build with comps groups and environments support" ON)
 option(WITH_MODULEMD "Build with modulemd modules support" ON)
 option(WITH_ZCHUNK "Build with zchunk delta compression support" ON)
+option(ENABLE_SOLV_URPMREORDER "Build with support for URPM-like solution reordering?" OFF)
 
 # build options - documentation
 option(WITH_HTML "Build HTML documentation" ON)
@@ -95,6 +96,11 @@ add_definitions(-DPROJECT_VERSION_MAJOR=${PROJECT_VERSION_MAJOR})
 add_definitions(-DPROJECT_VERSION_MINOR=${PROJECT_VERSION_MINOR})
 add_definitions(-DPROJECT_VERSION_PATCH=${PROJECT_VERSION_PATCH})
 
+# libsolv options
+if(ENABLE_SOLV_URPMREORDER)
+    add_definitions(-DLIBSOLV_FLAG_URPMREORDER=1)
+endif()
+
 if(WITH_SANITIZERS)
     message(WARNING "Building with sanitizers enabled!")
     add_compile_options(-fsanitize=address -fsanitize=undefined -fsanitize=leak)

libdnf5/rpm/solv/goal_private.cpp

@@ -103,7 +103,6 @@ void init_solver(libdnf5::solv::Pool & pool, libdnf5::solv::Solver & solver) {
     /* support package splits via obsoletes */
     solver.set_flag(SOLVER_FLAG_YUM_OBSOLETES, 1);
 
-// TODO Ask Neal whether it is needed. See https://bugs.mageia.org/show_bug.cgi?id=18315
 #if defined(LIBSOLV_FLAG_URPMREORDER)
     /* support urpm-like solution reordering */
     solver.set_flag(SOLVER_FLAG_URPM_REORDER, 1);