From b53587b72a3b2749cde347c60050a9258a86ba5f Mon Sep 17 00:00:00 2001
From: Sam Ravnborg <sam@neptun.(none)>
Date: Fri, 19 Oct 2007 21:46:01 +0200
Subject: [PATCH] --- yaml --- r: 71663 b: refs/heads/master c:
 910b40468a9ce3f2f5d48c5d260329c27d45adb5 h: refs/heads/master i:   71661:
 e0a08bd475b67bf6260513716255d54fc40b3478   71659:
 398902df0f1408bf3c48fed0583948df7ed9a933   71655:
 03f66a9e0b843ace99e730f69ebd0065dd2fbaa8   71647:
 df8799facd02f2135bce3e409d545362ffe0064b v: v3

---
 [refs]                                   |  2 +-
 trunk/Documentation/kbuild/makefiles.txt | 22 ++++++++++++++++++++++
 trunk/scripts/Kbuild.include             | 11 +++++++++++
 3 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 488a609c90f0..2dbf630583be 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 50a8ec31c3a00594ceb7c5f1dcf2ecdaf6a5b847
+refs/heads/master: 910b40468a9ce3f2f5d48c5d260329c27d45adb5
diff --git a/trunk/Documentation/kbuild/makefiles.txt b/trunk/Documentation/kbuild/makefiles.txt
index f099b814d383..6166e2d7da76 100644
--- a/trunk/Documentation/kbuild/makefiles.txt
+++ b/trunk/Documentation/kbuild/makefiles.txt
@@ -518,6 +518,28 @@ more details, with real examples.
 	In this example for a specific GCC version the build will error out explaining
 	to the user why it stops.
 
+    cc-cross-prefix
+	cc-cross-prefix is used to check if there exist a $(CC) in path with
+	one of the listed prefixes. The first prefix where there exist a
+	prefix$(CC) in the PATH is returned - and if no prefix$(CC) is found
+	then nothing is returned.
+	Additional prefixes are separated by a single space in the
+	call of cc-cross-prefix.
+	This functionality is usefull for architecture Makefile that try
+	to set CROSS_COMPILE to well know values but may have several
+	values to select between.
+	It is recommended only to try to set CROSS_COMPILE is it is a cross
+	build (host arch is different from target arch). And is CROSS_COMPILE
+	is already set then leave it with the old value.
+
+	Example:
+		#arch/m68k/Makefile
+		ifneq ($(SUBARCH),$(ARCH))
+		        ifeq ($(CROSS_COMPILE),)
+		               CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu-)
+			endif
+		endif
+
 === 4 Host Program support
 
 Kbuild supports building executables on the host for use during the
diff --git a/trunk/scripts/Kbuild.include b/trunk/scripts/Kbuild.include
index de7bb284c611..b96ea8d6a5ed 100644
--- a/trunk/scripts/Kbuild.include
+++ b/trunk/scripts/Kbuild.include
@@ -56,6 +56,17 @@ endef
 # gcc support functions
 # See documentation in Documentation/kbuild/makefiles.txt
 
+# cc-cross-prefix
+# Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)
+# Return first prefix where a prefix$(CC) is found in PATH.
+# If no $(CC) found in PATH with listed prefixes return nothing
+cc-cross-prefix =  \
+	$(word 1, $(foreach c,$(1),                                   \
+		$(shell set -e;                                       \
+		if (which $(strip $(c))$(CC)) > /dev/null 2>&1 ; then \
+			echo $(c);                                    \
+		fi)))
+
 # output directory for tests below
 TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/)