[PATCH 2/7] header-vars: new variable $(am__running_with_option)

[Stefano Lattarini]

This is a preparatory refactoring, needed by later patches.
No semantic change is intended.

* lib/am/header-vars.am (am__running_with_option): New, contains
shell code that determines whether the current make instance is
running with a given one-letter option (e.g., -k, -n) that takes
no argument.  Actually, the only supported option at the moment
is '-n' (support for '-k' will be added soon).
(am__make_dryrun): Rewrite as a thin wrapper around
'$(am__make_running_with_option)'.

Signed-off-by: Stefano Lattarini <address@hidden>
---
 lib/am/header-vars.am | 34 +++++++++++++++++++++++-----------
 1 file changed, 23 insertions(+), 11 deletions(-)

diff --git a/lib/am/header-vars.am b/lib/am/header-vars.am
index d2f0984..8426dcb 100644
--- a/lib/am/header-vars.am
+++ b/lib/am/header-vars.am
@@ -31,21 +31,26 @@ VPATH = @srcdir@
 ## enough for now.
 am__is_gnu_make = test -n '$(MAKEFILE_LIST)' && test -n '$(MAKELEVEL)'
 
-## Shell code that determines whether make is running in "dry mode"
-## ("make -n") or not.  Useful in rules that invoke make recursively,
-## and are thus executed also with "make -n" -- either because they
-## are declared as dependencies to '.MAKE' (NetBSD make), or because
-## their recipes contain the "$(MAKE)" string (GNU and Solaris make).
-am__make_dryrun = \
+## Shell code that determines whether the current make instance is
+## running with a given one-letter option (e.g., -k, -n) that takes
+## no argument.  Actually, the only supported option at the moment
+## is '-n' (support for '-k' will be added soon).
+am__make_running_with_option = \
   { \
-    am__dry=no; \
+    case $${am__target_option-} in \
+        n) ;; \
+        *) echo "am__make_running_with_option: internal error: invalid" \
+               "target option '$${am__target_option-}' specified" >&2; \
+           exit 1;; \
+    esac; \
+    am__has_opt=no; \
     if $(am__is_gnu_make); then \
 ## GNU make: $(MAKEFLAGS) is quite tricky there, and the older
 ## $(MFLAGS) variable behaves much better.
       for am__flg in $$MFLAGS; do \
         case $$am__flg in \
           *=*|--*) ;; \
-          -*n*) am__dry=yes; break;; \
+          -*$$am__target_option*) am__has_opt=yes; break;; \
         esac; \
       done; \
     else \
@@ -59,7 +64,7 @@ am__make_dryrun = \
 ## This has already happened in practice.  So we need this unpleasant hack.
          *\\[\ \       ]*) \
            echo 'am--echo: ; @echo "AM"  OK' | $(MAKE) -f - 2>/dev/null \
-             | grep '^AM OK$$' >/dev/null || am__dry=yes ;; \
+             | grep '^AM OK$$' >/dev/null || am__has_opt=yes ;; \
          *) \
           am__skip_next=no; \
            for am__flg in $$MAKEFLAGS; do \
@@ -72,14 +77,21 @@ am__make_dryrun = \
 ## 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;; \
+               *$$am__target_option*) am__has_opt=yes; break;; \
              esac; \
            done ;;\
        esac; \
     fi; \
-    test $$am__dry = yes; \
+    test $$am__has_opt = yes; \
   }
 
+## Shell code that determines whether make is running in "dry mode"
+## ("make -n") or not.  Useful in rules that invoke make recursively,
+## and are thus executed also with "make -n" -- either because they
+## are declared as dependencies to '.MAKE' (NetBSD make), or because
+## their recipes contain the "$(MAKE)" string (GNU and Solaris make).
+am__make_dryrun = { am__target_option=n; $(am__make_running_with_option); }
+
 ## Some derived variables that have been found to be useful.
 pkgdatadir = $(datadir)/@PACKAGE@
 pkgincludedir = $(includedir)/@PACKAGE@
-- 
1.8.2.1.610.g562af5b