toolchain-external: add a specific check to avoid Angstrom toolchains

The Angstrom toolchains available at
http://www.angstrom-distribution.org/toolchains/ are not usable as
external toolchains in Buildroot, because they are not pure toolchains
with just the C library, but instead complete SDKs with many
cross-compiled libraries (Gtk, Qt, glib, neon, sqlite, X.org, and many
more, approximately 200 MB of libraries).

Buildroot cannot use such toolchains, and while this is documented in
our manual, some users still try to do this. Today, one such user came
on the IRC channel, reporting a build problem, which we started
investigating, only to realize after a long time that he was using an
Angstrom toolchain.

To avoid this problem in the future, we explicitly check if the
toolchain is from Angstrom by looking at the vendor part of the tuple
exposed by the toolchain: as soon as it is
<something>-angstrom-<something-else>, we reject the toolchain with an
explanation.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

diff --git a/toolchain/helpers.mk b/toolchain/helpers.mk
index 95120cd97b11d3337eb9ce42adb682a6a9564336..a8944ce0f6d40ffa6ba70dae13017f74ae516c8a 100644 (file)
--- a/toolchain/helpers.mk
+++ b/toolchain/helpers.mk
@@ -324,3 +324,21 @@ check_cross_compiler_exists = \
                echo "Cannot execute cross-compiler '$${__CROSS_CC}'" ; \
                exit 1 ; \
        fi
+
+#
+# Check for toolchains known not to work with Buildroot. For now, we
+# only check for Angstrom toolchains, by looking at the vendor part of
+# the host tuple.
+#
+# $1: cross-gcc path
+#
+check_unusable_toolchain = \
+       __CROSS_CC=$(strip $1) ; \
+       vendor=`$${__CROSS_CC} -dumpmachine | cut -f2 -d'-'` ; \
+       if test "$${vendor}" = "angstrom" ; then \
+               echo "Angstrom toolchains are not pure toolchains: they contain" ; \
+               echo "many other libraries than just the C library, which makes" ; \
+               echo "them unsuitable as external toolchains for build systems" ; \
+               echo "such as Buildroot." ; \
+               exit 1 ; \
+       fi

diff --git a/toolchain/toolchain-external/toolchain-external.mk b/toolchain/toolchain-external/toolchain-external.mk
index b5b1ce78a2ba092b7a157c0fff5c25dd55e8ec00..d41cc7cfcb1a1f0a47156e46f462458429a8918a 100644 (file)
--- a/toolchain/toolchain-external/toolchain-external.mk
+++ b/toolchain/toolchain-external/toolchain-external.mk
@@ -371,6 +371,7 @@ endif
 # type of C library and all C library features.
 define TOOLCHAIN_EXTERNAL_CONFIGURE_CMDS
        $(Q)$(call check_cross_compiler_exists,$(TOOLCHAIN_EXTERNAL_CC))
+       $(Q)$(call check_unusable_toolchain,$(TOOLCHAIN_EXTERNAL_CC))
        $(Q)LIBC_A_LOCATION=`readlink -f $$(LANG=C $(TOOLCHAIN_EXTERNAL_CC) -print-file-name=libc.a)` ; \
        SYSROOT_DIR=`echo $${LIBC_A_LOCATION} | sed -r -e 's:(usr/)?lib(32|64)?/(.*/)?libc\.a::'` ; \
        if test -z "$${SYSROOT_DIR}" ; then \