Hi Sandro,
I'm forwarding the patches included in the spatialite & spatialite-tools Debian packages that are still applied to 4.3.0RC0.
These patches shouldn't be Debian specific, so please consider including these in the next release.
spatialite patches:
- 00-add_automake_foreign.patch
  add 'foreign' to AUTOMAKE_OPTIONS, required for autoreconf to enforce the GNU standards.
- 07-fix_spatialite_pc.patch
  avoid relinking sqlite3 and math libraries
- 11-link-libxml2.patch
  Link libxml2 for successfull test case build
- 12-link-pthread.patch
  Link libpthread to fix check_multithread build failure
spatialite-tools patches:
- 01-add_automake_foreign.patch
  add 'foreign' to AUTOMAKE_OPTIONS, required for autoreconf to enforce the GNU standards.
- 01-link-sqlite3.patch
  Update 
configure.ac to detect and link sqlite3 just like spatialite does now
- 10-no-sqlite-check.patch
   Don't require exact sqlite3 version match.
   SQLite allows cautious programmers to "insure that the application is compiled with matching library and header files."
   spatialite shouldn't require this to allow it run.
Kind Regards,
Bas