[OE-core] [RFC][PATCH] cmake-native: work around gcc6's '-isystem'-allergy

[Andreas Müller]

On Wed, Aug 31, 2016 at 11:25 AM, Jack Mitchell <ml at embed.me.uk> wrote:
> On 30/08/16 18:14, Andreas Müller wrote:
>>
>> since gcc6 we see many cmake/c++ based packets failing with:
>>
>> | fatal error: stdlib.h: No such file or directory
>>
>> a fix from gcc is not to expect [1] so work around by replacing '-isystem'
>> by
>> '-I' for c++.
>>
>> Build tested with many recipes in meta-qt5-extra / meta-oe inheriting
>> cmake.
>>
>> [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70129
>>
>> Signed-off-by: Andreas Müller <schnitzeltony at googlemail.com>
>> ---
>>  meta/recipes-devtools/cmake/cmake-native_3.6.1.bb  |  1 +
>>  .../0001-GNU.cmake-replace-isystem-by-I.patch      | 42
>> ++++++++++++++++++++++
>>  2 files changed, 43 insertions(+)
>>  create mode 100644
>> meta/recipes-devtools/cmake/cmake/0001-GNU.cmake-replace-isystem-by-I.patch
>>
>> diff --git a/meta/recipes-devtools/cmake/cmake-native_3.6.1.bb
>> b/meta/recipes-devtools/cmake/cmake-native_3.6.1.bb
>> index 33930fb..900091e 100644
>> --- a/meta/recipes-devtools/cmake/cmake-native_3.6.1.bb
>> +++ b/meta/recipes-devtools/cmake/cmake-native_3.6.1.bb
>> @@ -6,6 +6,7 @@ DEPENDS += "bzip2-native zlib-native"
>>
>>  SRC_URI += "\
>>      file://cmlibarchive-disable-ext2fs.patch \
>> +    file://0001-GNU.cmake-replace-isystem-by-I.patch \
>>  "
>>
>>  # Disable ccmake since we don't depend on ncurses
>> diff --git
>> a/meta/recipes-devtools/cmake/cmake/0001-GNU.cmake-replace-isystem-by-I.patch
>> b/meta/recipes-devtools/cmake/cmake/0001-GNU.cmake-replace-isystem-by-I.patch
>> new file mode 100644
>> index 0000000..4c06490
>> --- /dev/null
>> +++
>> b/meta/recipes-devtools/cmake/cmake/0001-GNU.cmake-replace-isystem-by-I.patch
>> @@ -0,0 +1,42 @@
>> +From a84d20abe6bc68f8d1a597a22af1ca98d62a5ce4 Mon Sep 17 00:00:00 2001
>> +From: =?UTF-8?q?Andreas=20M=C3=BCller?= <schnitzeltony at googlemail.com>
>> +Date: Fri, 26 Aug 2016 12:14:12 +0200
>> +Subject: [PATCH] GNU.cmake: replace -isystem by -I
>> +MIME-Version: 1.0
>> +Content-Type: text/plain; charset=UTF-8
>> +Content-Transfer-Encoding: 8bit
>> +
>> +since gcc6 we see many c++ based packes failing with:
>> +
>> +| fatal error: stdlib.h: No such file or directory
>> +
>> +a fix from gcc is not to expect [1] so work around
>> +
>> +[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70129
>> +
>> +Upstream-Status: Pending
>> +
>> +Signed-off-by: Andreas Müller <schnitzeltony at googlemail.com>
>> +---
>> + Modules/Compiler/GNU.cmake | 6 +++++-
>> + 1 file changed, 5 insertions(+), 1 deletion(-)
>> +
>> +diff --git a/Modules/Compiler/GNU.cmake b/Modules/Compiler/GNU.cmake
>> +index c2d393d..9d1477d 100644
>> +--- a/Modules/Compiler/GNU.cmake
>> ++++ b/Modules/Compiler/GNU.cmake
>> +@@ -53,6 +53,10 @@ macro(__compiler_gnu lang)
>> +   set(CMAKE_${lang}_CREATE_PREPROCESSED_SOURCE "<CMAKE_${lang}_COMPILER>
>> <DEFINES> <INCLUDES> <FLAGS> -E <SOURCE> > <PREPROCESSED_SOURCE>")
>> +   set(CMAKE_${lang}_CREATE_ASSEMBLY_SOURCE "<CMAKE_${lang}_COMPILER>
>> <DEFINES> <INCLUDES> <FLAGS> -S <SOURCE> -o <ASSEMBLY_SOURCE>")
>> +   if(NOT APPLE OR NOT CMAKE_${lang}_COMPILER_VERSION VERSION_LESS 4) #
>> work around #4462
>> +-    set(CMAKE_INCLUDE_SYSTEM_FLAG_${lang} "-isystem ")
>> ++    if("${lang}" STREQUAL "CXX")
>> ++      set(CMAKE_INCLUDE_SYSTEM_FLAG_${lang} "-I ")
>> ++    else()
>> ++      set(CMAKE_INCLUDE_SYSTEM_FLAG_${lang} "-isystem ")
>> ++    endif()
>> +   endif()
>> + endmacro()
>> +--
>> +2.5.5
>> +
>>
>
> Thanks for the patch Andreas, this fixes my build for now but as you
> mentioned is a bit of a hack to get round the issue. As this fixes my
> problem does it mean that it's not bitbake which is injecting the isystem,
> but instead a CMake recipe somewhere?
>
> Regards,
> Jack.
> --
I don't know your recipe but I think -isystem in bitbake.conf would
only cause trouble for native recipes.

As a heavy cmake-qt5 user (kde/lxqt/hawaii) I had many failing
cross-recipes not finding stdlib.h. After reading the gcc-bug I check
compile logs and they were full of -isystem on sysroot/usr/include -
had no idea where they came from.
First I grepped oe-core but did not find suspicious (e.g bitbake.conf
- see above). Then I grepped cmake sources and found GNU.cmake,
patched it to affect c++ only and my build errors were gone.

Andreas