[PATCH v2] kbuild: check for pkg-config on make {menu,n,g,x}config

[Randy Dunlap]

From: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>

Each of 'make {menu,n,g,x}config' uses (needs) pkg-config to make sure
that other required files are present, but none of these check that
pkg-config itself is present.  Add a check for all 4 of these targets.

Fixes kernel bugzilla #77511:
https://bugzilla.kernel.org/show_bug.cgi?id=77511

Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
---
v2: use 'command -v' instead of 'which'

I'm also OK with just documenting the pkg-config requirement in
Documentation/Changes (= Documentation/process/changes.rst).

 scripts/kconfig/Makefile           |   15 ++++++++++++++-
 scripts/kconfig/check-pkgconfig.sh |   12 ++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

--- lnx-416-rc3.orig/scripts/kconfig/Makefile
+++ lnx-416-rc3/scripts/kconfig/Makefile
@@ -160,6 +160,9 @@ help:
 	@echo  '  xenconfig       - Enable additional options for xen dom0 and guest kernel support'
 	@echo  '  tinyconfig	  - Configure the tiniest possible kernel'
 
+# pkg-config check
+check-pkgconfig  := $(srctree)/$(src)/check-pkgconfig.sh
+
 # lxdialog stuff
 check-lxdialog  := $(srctree)/$(src)/lxdialog/check-lxdialog.sh
 
@@ -205,7 +208,17 @@ $(addprefix $(obj)/, mconf.o $(lxdialog)
 $(obj)/dochecklxdialog:
 	$(Q)$(CONFIG_SHELL) $(check-lxdialog) -check $(HOSTCC) $(HOST_EXTRACFLAGS) $(HOSTLOADLIBES_mconf)
 
-always := dochecklxdialog
+# Check that we have pkg-config (used by each of menu/n/g/xconfig)
+PHONY += $(obj)/docheckpkgconfig
+$(addprefix $(obj)/, mconf.o): $(obj)/docheckpkgconfig
+$(addprefix $(obj)/, nconf.o): $(obj)/docheckpkgconfig
+$(addprefix $(obj)/, gconf.o): $(obj)/docheckpkgconfig
+$(addprefix $(obj)/, qconf.o): $(obj)/docheckpkgconfig
+
+$(obj)/docheckpkgconfig:
+	$(Q)$(CONFIG_SHELL) $(check-pkgconfig)
+
+always := docheckpkgconfig dochecklxdialog
 
 # Add environment specific flags
 HOST_EXTRACFLAGS += $(shell $(CONFIG_SHELL) $(srctree)/$(src)/check.sh $(HOSTCC) $(HOSTCFLAGS))
--- /dev/null
+++ lnx-416-rc3/scripts/kconfig/check-pkgconfig.sh
@@ -0,0 +1,12 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# Check for pkg-config presence
+
+pkgcfg=`command -v pkg-config`
+
+if [ "$pkgcfg" = "" ]; then
+	echo "'make *config' requires 'pkg-config'. Please install it." 1>&2
+	exit 1		# error
+fi
+
+exit 0