[PATCHv3] Config.in: add symbols for BR2_HOST_GCC_AT_LEAST_X_Y

From: Arnout Vandecappelle <arnout@mind.be>

Some host packages need a recent gcc version. Add symbols to Config.in
to specify the HOSTCC version. The values are passed through the
environment, and this environment is generated in a new support script.

Also update the documentation to mention the new symbols.

[Thomas: simplify by using only make logic instead of an external
shell script.]

Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
This is an alternate version, in which I've removed the shell script,
and did everything in make. Contrary to what Arnout said, I don't find
the sed expression to be more complicated, and the condition on gcc <=
4 or gcc >= 5 can easily be done in make.

 Config.in                                 | 24 ++++++++++++++++++++++++
 Makefile                                  | 12 ++++++++++++
 docs/manual/adding-packages-directory.txt |  7 +++++++
 3 files changed, 43 insertions(+)

THomas, Arnout, All,

On 2015-12-31 00:08 +0100, Thomas Petazzoni spake thusly:
> From: Arnout Vandecappelle <arnout@mind.be>
> 
> Some host packages need a recent gcc version. Add symbols to Config.in
> to specify the HOSTCC version. The values are passed through the
> environment, and this environment is generated in a new support script.
> 
> Also update the documentation to mention the new symbols.
> 
> [Thomas: simplify by using only make logic instead of an external
> shell script.]
> 
> Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

Regards,
Yann E. MORIN.

> ---
> This is an alternate version, in which I've removed the shell script,
> and did everything in make. Contrary to what Arnout said, I don't find
> the sed expression to be more complicated, and the condition on gcc <=
> 4 or gcc >= 5 can easily be done in make.
> 
>  Config.in                                 | 24 ++++++++++++++++++++++++
>  Makefile                                  | 12 ++++++++++++
>  docs/manual/adding-packages-directory.txt |  7 +++++++
>  3 files changed, 43 insertions(+)
> 
> diff --git a/Config.in b/Config.in
> index 9513cc1..bbbefb0 100644
> --- a/Config.in
> +++ b/Config.in
> @@ -18,6 +18,30 @@ config BR2_EXTERNAL
>  	string
>  	option env="BR2_EXTERNAL"
>  
> +# Hidden config symbols for packages to check system gcc version
> +config BR2_HOST_GCC_VERSION
> +	string
> +	option env="HOST_GCC_VERSION"
> +
> +config BR2_HOST_GCC_AT_LEAST_4_7
> +	bool
> +	default y if BR2_HOST_GCC_VERSION = "47"
> +
> +config BR2_HOST_GCC_AT_LEAST_4_8
> +	bool
> +	default y if BR2_HOST_GCC_VERSION = "48"
> +	select BR2_HOST_GCC_AT_LEAST_4_7
> +
> +config BR2_HOST_GCC_AT_LEAST_4_9
> +	bool
> +	default y if BR2_HOST_GCC_VERSION = "49"
> +	select BR2_HOST_GCC_AT_LEAST_4_8
> +
> +config BR2_HOST_GCC_AT_LEAST_5
> +	bool
> +	default y if BR2_HOST_GCC_VERSION = "5"
> +	select BR2_HOST_GCC_AT_LEAST_4_9
> +
>  # Hidden boolean selected by packages in need of Java in order to build
>  # (example: xbmc)
>  config BR2_NEEDS_HOST_JAVA
> diff --git a/Makefile b/Makefile
> index 1d69192..0cfca6c 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -293,6 +293,17 @@ HOSTRANLIB := $(shell which $(HOSTRANLIB) || type -p $(HOSTRANLIB) || echo ranli
>  export HOSTAR HOSTAS HOSTCC HOSTCXX HOSTLD
>  export HOSTCC_NOCCACHE HOSTCXX_NOCCACHE
>  
> +HOSTCC_VERSION := $(shell $(HOSTCC_NOCCACHE) --version | \
> +	sed 's/^.* \([0-9]*\)\.\([0-9]*\)\.\([0-9]*\)[ ]*.*/\1 \2/')
> +
> +# For gcc 4.x, keep the second number around. For gcc >= 5.x, the
> +# major version is enough.
> +ifeq ($(firstword $(HOSTCC_VERSION)),4)
> +HOSTCC_VERSION := $(subst $(space),,$(HOSTCC_VERSION))
> +else
> +HOSTCC_VERSION := $(firstword $(HOSTCC_VERSION))
> +endif
> +
>  # Make sure pkg-config doesn't look outside the buildroot tree
>  HOST_PKG_CONFIG_PATH := $(PKG_CONFIG_PATH)
>  unexport PKG_CONFIG_PATH
> @@ -724,6 +735,7 @@ COMMON_CONFIG_ENV = \
>  	KCONFIG_TRISTATE=$(BUILD_DIR)/buildroot-config/tristate.config \
>  	BR2_CONFIG=$(BR2_CONFIG) \
>  	BR2_EXTERNAL=$(BR2_EXTERNAL) \
> +	HOST_GCC_VERSION=$(HOSTCC_VERSION) \
>  	SKIP_LEGACY=
>  
>  xconfig: $(BUILD_DIR)/buildroot-config/qconf outputmakefile
> diff --git a/docs/manual/adding-packages-directory.txt b/docs/manual/adding-packages-directory.txt
> index 139123e..c2d9f75 100644
> --- a/docs/manual/adding-packages-directory.txt
> +++ b/docs/manual/adding-packages-directory.txt
> @@ -283,6 +283,13 @@ use in the comment.
>  ** Comment string: +gcc >= X.Y+ and/or `gcc <= X.Y` (replace
>     +X.Y+ with the proper version)
>  
> +* Host GCC version
> +** Dependency symbol: +BR2_HOST_GCC_AT_LEAST_X_Y+, (replace
> +   +X_Y+ with the proper version, see +Config.in+)
> +** Comment string: no comment to be added
> +** Note that it is usually not the package itself that has a minimum
> +   host GCC version, but rather a host-package on which it depends.
> +
>  * C library
>  ** Dependency symbol: +BR2_TOOLCHAIN_USES_GLIBC+,
>     +BR2_TOOLCHAIN_USES_MUSL+, +BR2_TOOLCHAIN_USES_UCLIBC+
> -- 
> 2.6.4
>