[Buildroot] [PATCH v2 1/2] Config.in: add symbols for BR2_HOST_GCC_AT_LEAST_X_Y

[Arnout Vandecappelle (Essensium/Mind)]

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.

Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout at mind.be>
---
v2: Use a single environment variable and select statements (Yann)
    This makes the shell script ridiculously simple. I've tried to move
    it to the Makefile, but then all the additional quoting etc. makes
    it complicated again.
---
 Config.in                                 | 24 ++++++++++++++++++++++
 Makefile                                  |  1 +
 docs/manual/adding-packages-directory.txt |  7 +++++++
 support/scripts/gcc-version-variables     | 33 +++++++++++++++++++++++++++++++
 4 files changed, 65 insertions(+)
 create mode 100755 support/scripts/gcc-version-variables

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..93fae7d 100644
--- a/Makefile
+++ b/Makefile
@@ -724,6 +724,7 @@ COMMON_CONFIG_ENV = \
 	KCONFIG_TRISTATE=$(BUILD_DIR)/buildroot-config/tristate.config \
 	BR2_CONFIG=$(BR2_CONFIG) \
 	BR2_EXTERNAL=$(BR2_EXTERNAL) \
+	$(shell support/scripts/gcc-version-variables $(HOSTCC_NOCCACHE)) \
 	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+
diff --git a/support/scripts/gcc-version-variables b/support/scripts/gcc-version-variables
new file mode 100755
index 0000000..346215d
--- /dev/null
+++ b/support/scripts/gcc-version-variables
@@ -0,0 +1,33 @@
+#! /bin/sh
+#
+# Print the environment variables for top-level Config.in's
+# HOST_GCC_AT_LEAST_X_Y. First argument is the compiler.
+#
+# Copyright (C) 2014 by the Buildroot developers <buildroot at buildroot.org>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+#
+
+HOSTCC_NOCCACHE="$1"
+
+# hostcc version as an integer - E.G. 4.9.2 => 49
+HOSTCC_VERSION=$(${HOSTCC_NOCCACHE} --version | \
+    sed -n 's/^.* \([0-9]*\)\.\([0-9]*\)\.\([0-9]*\)[ ]*.*$/\1\2/p')
+
+if [ "$HOSTCC_VERSION" -ge 50 ]; then
+    HOSTCC_VERSION=${HOSTCC_VERSION%?}
+fi
+printf "HOST_GCC_VERSION=%d " "$HOSTCC_VERSION"
+
-- 
2.6.4