build: print build options after configure

Co-authored-by: UdjinM6 <UdjinM6@users.noreply.github.com>

configure.ac

@@ -842,3 +842,20 @@ AC_OUTPUT
 dnl Peplace conflict-prone PACKAGE-prefixed macros with DASHBLS
 sed -i.old 's/PACKAGE/DASHBLS/g' depends/relic/include/relic_conf.h
 sed -i.old 's/PACKAGE/DASHBLS/g' config.status
+
+echo
+echo "Options used to compile and link:"
+echo "  target os           = $TARGET_OS"
+echo "  backend             = $want_backend"
+echo "  build bench         = $BUILD_BENCH"
+echo "  build test          = $BUILD_TEST"
+echo "  use debug           = $use_debug"
+echo "  use hardening       = $use_hardening"
+echo "  use optimizations   = $use_optimizations"
+echo
+echo "  LDFLAGS             = $HARDENED_LDFLAGS $CORE_LDFLAGS $GMP_LDFLAGS"
+echo "  CFLAGS              = $DEBUG_FLAGS $HARDENED_FLAGS $CORE_FLAGS $WARN_FLAGS $NOWARN_FLAGS"
+echo "  CPPFLAGS            = $CORE_CPPFLAGS $GMP_CPPFLAGS"
+echo "  CXXFLAGS            = $DEBUG_FLAGS $HARDENED_FLAGS $CORE_FLAGS $WARN_FLAGS $NOWARN_FLAGS"
+echo "  PTHREAD_FLAGS       = $PTHREAD_CFLAGS $PTHREAD_LIBS"
+echo