Enhance build system so that "make V=1" works like the Linux Kernel

If gmake is available, the developer can use "make V=1" instead of
using a configure-time switch, --enable-verbose-makecmds, to see all
of the commands executed by the Makefile.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 81 insertions, 0 deletions

diff --git a/aclocal.m4 b/aclocal.m4
index 3c32c839..6fd4652c 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -2694,3 +2694,84 @@ if test -n "$PKG_CONFIG"; then
                
 fi[]dnl
 ])# PKG_PROG_PKG_CONFIG
+# ===========================================================================
+#         http://www.nongnu.org/autoconf-archive/check_gnu_make.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   CHECK_GNU_MAKE()
+#
+# DESCRIPTION
+#
+#   This macro searches for a GNU version of make. If a match is found, the
+#   makefile variable `ifGNUmake' is set to the empty string, otherwise it
+#   is set to "#". This is useful for including a special features in a
+#   Makefile, which cannot be handled by other versions of make. The
+#   variable _cv_gnu_make_command is set to the command to invoke GNU make
+#   if it exists, the empty string otherwise.
+#
+#   Here is an example of its use:
+#
+#   Makefile.in might contain:
+#
+#       # A failsafe way of putting a dependency rule into a makefile
+#       $(DEPEND):
+#               $(CC) -MM $(srcdir)/*.c > $(DEPEND)
+#
+#       @ifGNUmake@ ifeq ($(DEPEND),$(wildcard $(DEPEND)))
+#       @ifGNUmake@ include $(DEPEND)
+#       @ifGNUmake@ endif
+#
+#   Then configure.in would normally contain:
+#
+#       CHECK_GNU_MAKE()
+#       AC_OUTPUT(Makefile)
+#
+#   Then perhaps to cause gnu make to override any other make, we could do
+#   something like this (note that GNU make always looks for GNUmakefile
+#   first):
+#
+#       if  ! test x$_cv_gnu_make_command = x ; then
+#               mv Makefile GNUmakefile
+#               echo .DEFAULT: > Makefile ;
+#               echo \  $_cv_gnu_make_command \$@ >> Makefile;
+#       fi
+#
+#   Then, if any (well almost any) other make is called, and GNU make also
+#   exists, then the other make wraps the GNU make.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 John Darrington <j.darrington@elvis.murdoch.edu.au>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved.
+#
+# Note: Modified by Ted Ts'o to add @ifNotGNUMake@
+
+AC_DEFUN(
+        [CHECK_GNU_MAKE], [ AC_CACHE_CHECK( for GNU make,_cv_gnu_make_command,
+                _cv_gnu_make_command='' ;
+dnl Search all the common names for GNU make
+                for a in "$MAKE" make gmake gnumake ; do
+                        if test -z "$a" ; then continue ; fi ;
+                        if  ( sh -c "$a --version" 2> /dev/null | grep GNU  2>&1 > /dev/null ) ;  then
+                                _cv_gnu_make_command=$a ;
+                                break;
+                        fi
+                done ;
+        ) ;
+dnl If there was a GNU version, then set @ifGNUmake@ to the empty string, '#' otherwise
+        if test  "x$_cv_gnu_make_command" != "x"  ; then
+                ifGNUmake='' ;
+                ifNotGNUmake='#' ;
+        else
+                ifGNUmake='#' ;
+                ifNotGNUmake='' ;
+                AC_MSG_RESULT("Not found");
+        fi
+        AC_SUBST(ifGNUmake)
+        AC_SUBST(ifNotGNUmake)
+] )