kconfig: refactor Makefile to reduce process forks

Refactor Makefile and use read-file macro. For Make >= 4.2, it can read
out a file by using the built-in function.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

kbuild: Allow kernel installation packaging to override pkg-config

Add HOSTPKG_CONFIG to allow tooling that builds the kernel to override
what pkg-config and parameters are used.

Signed-off-by: Chun-Tse Shao <ctshao@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

kconfig: mconf: fix HOSTCC call

Commit c0f975af1745 ("kconfig: Support building mconf with vendor
sysroot ncurses") introduces a bug when HOSTCC contains parameters:
the whole command line is treated as the program name (with spaces
in it). Therefore, we have to remove the quotes.

Fixes: c0f975af1745 ("kconfig: Support building mconf with vendor sysroot ncurses")
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

kconfig: Support building mconf with vendor sysroot ncurses

Changes the final fallback path in the ncurses locator for mconf
to support host compilers with a non-default sysroot.

This is similar to the hardcoded search for ncurses under
'/usr/include', but can support compilers that keep their default
header and library directories elsewhere.

For nconfig, do nothing because the only vendor compiler I'm aware
of with this layout (Apple Clang) ships an ncurses version that's too
old for nconfig anyway.

Signed-off-by: John Millikin <john@john-millikin.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

kconfig: be more helpful if pkg-config is missing

If ncurses is installed, but at a non-default location, the previous
error message was not helpful in resolving the situation. Now it will
suggest that pkg-config might need to be installed in addition to
ncurses.

Signed-off-by: Alyssa Ross <hi@alyssa.is>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

kconfig: do not require pkg-config on make {menu,n}config

Meelis Roos reported a {menu,n}config regression:
"I have libncurses devel package installed in the default system
location (as do 99%+ on actual developers probably) and in this
case, pkg-config is useless. pkg-config is needed only when
libraries and headers are installed in non-default locations but
it is bad to require installation of pkg-config on all the machines
where make menuconfig would be possibly run."

For {menu,n}config, do not use pkg-config if it is not installed.
For {g,x}config, keep checking pkg-config since we really rely on it
for finding the installation paths of the required packages.

Fixes: 4ab3b80159d4 ("kconfig: check for pkg-config on make {menu,n,g,x}config")
Reported-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Meelis Roos <mroos@linux.ee>
Tested-by: Randy Dunlap <rdunlap@infradead.org>

kconfig: refactor ncurses package checks for building mconf and nconf

The mconf (or its infrastructure, lxdiaglog) depends on the ncurses.
Move and rename check-lxdialog.sh to mconf-cfg.sh to make it work in
the same way as for qconf and gconf.

This commit fixes some more weirdnesses.

The nconf also needs ncurses packages. HOSTLOADLIBES_nconf is set
to the libraries needed for nconf, but the cflags is not explicitly
set. Actually, nconf relies on the check-lxdialog.sh for the proper
cflags:

HOST_EXTRACFLAGS += $(shell $(CONFIG_SHELL) $(check-lxdialog) -ccflags) \
-DLOCALE

The code above passes the ncurses flags to all objects, even for conf,
qconf, gconf. Let's pass the ncurses flags only to mconf and nconf.

Currently, the presence of ncurses is not checked for nconf. Let's
show a prompt like the mconf case.

According to Randy's report, the shell scripts still need to carry
the fallback code in case the pkg-config fails to find the ncurses
packages.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>