[Buildroot] [PATCH 1/2] llvm: add dependency on !BR2_TOOLCHAIN_HAS_GCC_BUG_64735

[Thomas Petazzoni]

LLVM uses std::shared_future, which until gcc 7.x isn't available on
architectures that don't provide lock-free atomics, see
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64735.

Buildroot already has a BR2_TOOLCHAIN_HAS_GCC_BUG_64735 option to
handle such a case, so simply add this new dependency to LLVM. It will
make sure LLVM doesn't get built on ARMv5 platforms using a gcc older
than 7.x.

Fixes:

  http://autobuild.buildroot.net/results/ada497f6a8d20fa1a9adb2b17a138d7b726a6cdc/

Signed-off-by: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
---
 package/llvm/Config.in | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/package/llvm/Config.in b/package/llvm/Config.in
index 70f73f4858..15f2507ef2 100644
--- a/package/llvm/Config.in
+++ b/package/llvm/Config.in
@@ -18,6 +18,7 @@ config BR2_PACKAGE_LLVM
 	depends on BR2_TOOLCHAIN_GCC_AT_LEAST_4_8
 	depends on BR2_TOOLCHAIN_HAS_THREADS
 	depends on BR2_INSTALL_LIBSTDCPP
+	depends on !BR2_TOOLCHAIN_HAS_GCC_BUG_64735 # std::shared_future
 	help
 	  The LLVM Project is a collection of modular and reusable
 	  compiler and toolchain technologies.
@@ -38,3 +39,7 @@ comment "llvm needs a toolchain w/ threads, C++, gcc >= 4.8, host gcc >= 4.8"
 	depends on BR2_PACKAGE_LLVM_ARCH_SUPPORTS
 	depends on !BR2_TOOLCHAIN_HAS_THREADS || !BR2_INSTALL_LIBSTDCPP || \
 		!BR2_HOST_GCC_AT_LEAST_4_8 || !BR2_TOOLCHAIN_GCC_AT_LEAST_4_8
+
+comment "llvm needs a toolchain not affected by GCC bug 64735"
+	depends on BR2_PACKAGE_LLVM_ARCH_SUPPORTS
+	depends on BR2_TOOLCHAIN_HAS_GCC_BUG_64735
-- 
2.14.3