[PATCH] add XARGS to toplevel Makefile

[Olaf Hering <olaf@aepfle.de>]

run xargs with --no-run-if-empty to avoid random failures:

  MAKE   tags
ctags: No files specified. Try "ctags --help".
make: *** [tags] Error 123

Signed-off-by: Olaf Hering <olaf@aepfle.de>

---
 Makefile |   26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

Index: linux-2.6/Makefile
===================================================================
--- linux-2.6.orig/Makefile
+++ linux-2.6/Makefile
@@ -295,6 +295,8 @@ DEPMOD		= /sbin/depmod
 KALLSYMS	= scripts/kallsyms
 PERL		= perl
 CHECK		= sparse
+# assume xargs comes from GNU findutils or GNU coreutils
+XARGS		= $(shell if [ "$$(uname -s)" = "Linux" ]; then echo "xargs --no-run-if-empty" ; else echo "xargs" ; fi )
 
 CHECKFLAGS     := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ -Wbitwise $(CF)
 MODFLAGS	= -DMODULE
@@ -1049,7 +1051,7 @@ clean: archclean $(clean-dirs)
 		\( -name '*.[oas]' -o -name '*.ko' -o -name '.*.cmd' \
 		-o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
 		-o -name '*.symtypes' \) \
-		-type f -print | xargs rm -f
+		-type f -print | $(XARGS) rm -f
 
 # mrproper - Delete all generated files, including .config
 #
@@ -1075,7 +1077,7 @@ distclean: mrproper
 		-o -name '*.bak' -o -name '#*#' -o -name '.*.orig' \
 		-o -name '.*.rej' -o -size 0 \
 		-o -name '*%' -o -name '.*.cmd' -o -name 'core' \) \
-		-type f -print | xargs rm -f
+		-type f -print | $(XARGS) rm -f
 
 
 # Packaging of the kernel to various formats
@@ -1237,7 +1239,7 @@ clean: $(clean-dirs)
 	@find $(KBUILD_EXTMOD) $(RCS_FIND_IGNORE) \
 		\( -name '*.[oas]' -o -name '*.ko' -o -name '.*.cmd' \
 		-o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \) \
-		-type f -print | xargs rm -f
+		-type f -print | $(XARGS) rm -f
 
 help:
 	@echo  '  Building external modules.'
@@ -1313,26 +1315,26 @@ endef
 
 define xtags
 	if $1 --version 2>&1 | grep -iq exuberant; then \
-	    $(all-sources) | xargs $1 -a \
+	    $(all-sources) | $(XARGS) $1 -a \
 		-I __initdata,__exitdata,__acquires,__releases \
 		-I EXPORT_SYMBOL,EXPORT_SYMBOL_GPL \
 		--extra=+f --c-kinds=+px; \
-	    $(all-kconfigs) | xargs $1 -a \
+	    $(all-kconfigs) | $(XARGS) $1 -a \
 		--langdef=kconfig \
 		--language-force=kconfig \
 		--regex-kconfig='/^[[:blank:]]*config[[:blank:]]+([[:alnum:]_]+)/\1/'; \
-	    $(all-defconfigs) | xargs $1 -a \
+	    $(all-defconfigs) | $(XARGS) $1 -a \
 		--langdef=dotconfig \
 		--language-force=dotconfig \
 		--regex-dotconfig='/^#?[[:blank:]]*(CONFIG_[[:alnum:]_]+)/\1/'; \
 	elif $1 --version 2>&1 | grep -iq emacs; then \
-	    $(all-sources) | xargs $1 -a; \
-	    $(all-kconfigs) | xargs $1 -a \
+	    $(all-sources) | $(XARGS) $1 -a; \
+	    $(all-kconfigs) | $(XARGS) $1 -a \
 		--regex='/^[ \t]*config[ \t]+\([a-zA-Z0-9_]+\)/\1/'; \
-	    $(all-defconfigs) | xargs $1 -a \
+	    $(all-defconfigs) | $(XARGS) $1 -a \
 		--regex='/^#?[ \t]?\(CONFIG_[a-zA-Z0-9_]+\)/\1/'; \
 	else \
-	    $(all-sources) | xargs $1 -a; \
+	    $(all-sources) | $(XARGS) $1 -a; \
 	fi
 endef
 
@@ -1371,12 +1373,12 @@ tags: FORCE
 includecheck:
 	find * $(RCS_FIND_IGNORE) \
 		-name '*.[hcS]' -type f -print | sort \
-		| xargs $(PERL) -w scripts/checkincludes.pl
+		| $(XARGS) $(PERL) -w scripts/checkincludes.pl
 
 versioncheck:
 	find * $(RCS_FIND_IGNORE) \
 		-name '*.[hcS]' -type f -print | sort \
-		| xargs $(PERL) -w scripts/checkversion.pl
+		| $(XARGS) $(PERL) -w scripts/checkversion.pl
 
 namespacecheck:
 	$(PERL) $(srctree)/scripts/namespace.pl