makefiles: update doc

Document using of target useful for checking variable content.

diff --git a/Makefile.in b/Makefile.in
index 1d5aff4825d68cf1891bf67e813b786540de4a71..58f255d4dc9340fb201330f1139ab96c052884a0 100644 (file)
--- a/Makefile.in
+++ b/Makefile.in
@@ -171,6 +171,7 @@ help:
        @echo "  lcov-dated             Generate lcov with timedate suffix."
        @echo "  lcov-reset             Reset lcov counters"
        @echo "  man                    Build man pages."
+       @echo "  print-VARIABLE         Resolve make variable."
        @echo "  rpm                    Build rpm."
        @echo "  run-unit-test          Run unit tests."
        @echo "  tags                   Generate c/etags."