depend: prefer $(...) over `...` in Cygwin-specific recipes

On Cygwin, we can happily assume only POSIX-conforming shells exist.
This commit is useless by itself, but is useful as a preparatory
refactoring in view of a future change.

* lib/am/depend2.am: In recipes for producing '.obj' objects, use
the POSIX form $(...) for command substitution, rather than the
classic Bourne one `...`.

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

diff --git a/lib/am/depend2.am b/lib/am/depend2.am
index 5522aa36ab7e57148556c6052adadf538f0c9fe0..a947ee7b675a3b0916fc2657aed3d217c170b644 100644 (file)
--- a/lib/am/depend2.am
+++ b/lib/am/depend2.am
@@ -63,10 +63,10 @@ endif !%FASTDEP%
 if %FASTDEP%
        %VERBOSE%$(am__set_depbase) \
        && %COMPILE% -MT $@ -MD -MP -MF $$depbase.Tpo -c -o $@ %SOURCEFLAG% \
-?GENERIC?      `$(CYGPATH_W) '%SOURCE%'` \
+?GENERIC?      $$($(CYGPATH_W) '%SOURCE%') \
 ## For non-suffix rules, we must emulate a VPATH search on %SOURCE%.
-?!GENERIC?     `if test -f '%SOURCE%'; then $(CYGPATH_W) '%SOURCE%'; \
-?!GENERIC?      else $(CYGPATH_W) '$(srcdir)/%SOURCE%'; fi` \
+?!GENERIC?     $$(if test -f '%SOURCE%'; then $(CYGPATH_W) '%SOURCE%'; \
+?!GENERIC?        else $(CYGPATH_W) '$(srcdir)/%SOURCE%'; fi) \
        && $(am__mv) $$depbase.Tpo $$depbase.Po
 else !%FASTDEP%
 if %AMDEP%
@@ -74,10 +74,10 @@ if %AMDEP%
        DEPDIR=$(DEPDIR) $(%FPFX%DEPMODE) $(depcomp) @AMDEPBACKSLASH@
 endif %AMDEP%
        %VERBOSE-NODEP%%COMPILE% -c -o $@ %SOURCEFLAG% \
-?GENERIC?      `$(CYGPATH_W) '%SOURCE%'`
+?GENERIC?      $$($(CYGPATH_W) '%SOURCE%')
 ## For non-suffix rules, we must emulate a VPATH search on %SOURCE%.
-?!GENERIC?     `if test -f '%SOURCE%'; then $(CYGPATH_W) '%SOURCE%'; \
-?!GENERIC?      else $(CYGPATH_W) '$(srcdir)/%SOURCE%'; fi`
+?!GENERIC?     $$(if test -f '%SOURCE%'; then $(CYGPATH_W) '%SOURCE%'; \
+?!GENERIC?        else $(CYGPATH_W) '$(srcdir)/%SOURCE%'; fi)
 endif !%FASTDEP%
 endif %?NONLIBTOOL%