dry-run: don't get confused by '-I' option

Fixes automake bug#13760 for non-GNU make implementations that still
support the option '-I'.  So far, the only such make implementation
are FreeBSD (8.x) make and NetBSD (5.x) make.

* lib/am/header-vars.am (am__make_dryrun): If a non-GNU make is being
used, try to handle the '-I' option in $MAKEFLAGS correctly.  For GNU
make, that is already done by the proper use of the $MFLAGS variable.

Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>

diff --git a/lib/am/header-vars.am b/lib/am/header-vars.am
index 23c627e..d2f0984 100644 (file)
--- a/lib/am/header-vars.am
+++ b/lib/am/header-vars.am
@@ -61,9 +61,17 @@ am__make_dryrun = \
            echo 'am--echo: ; @echo "AM"  OK' | $(MAKE) -f - 2>/dev/null \
              | grep '^AM OK$$' >/dev/null || am__dry=yes ;; \
          *) \
+          am__skip_next=no; \
            for am__flg in $$MAKEFLAGS; do \
+            if test $$am__skip_next = yes; then \
+              am__skip_next=no; \
+              continue; \
+            fi; \
              case $$am__flg in \
                *=*|--*) ;; \
+## Quite ugly special-casing.  We might need other similar, but let's
+## wait until the need arises.
+              -I) am__skip_next=yes;; \
                *n*) am__dry=yes; break;; \
              esac; \
            done ;;\