[Buildroot] [PATCH] package/opencv3: fix CMAKE_CXX_FLAGS

[Buildroot] [PATCH] package/opencv3: fix CMAKE_CXX_FLAGS

[Max Filippov]

The commit 4904c4c "package/opencv3: use BR2_TOOLCHAIN_HAS_LIBATOMIC"
overrides CMAKE_CXX_FLAGS with the single -latomic, losing all ABI
CFLAGS that are passed there by default. This breaks build on xtensa
where ABI CFLAGS contain important code generation options.

Append $(TARGET_CXXFLAGS) to CMAKE_CXX_FLAGS along with -latomic.

Fixes:
  http://autobuild.buildroot.net/results/7f1c96abd8fbb5b358a07100ab623316e9bb9dcd
  http://autobuild.buildroot.net/results/e0c93d0f6d1da0d62d4dbba211a275bfe75e9645
  http://autobuild.buildroot.net/results/53e7e4b4b6a7b48b8012799d7507f7594dbf01b2

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 package/opencv3/opencv3.mk | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/package/opencv3/opencv3.mk b/package/opencv3/opencv3.mk
index 2529de9..10660a9 100644
--- a/package/opencv3/opencv3.mk
+++ b/package/opencv3/opencv3.mk
@@ -12,7 +12,7 @@ OPENCV3_LICENSE_FILES = LICENSE
 
 # Uses __atomic_fetch_add_4
 ifeq ($(BR2_TOOLCHAIN_HAS_LIBATOMIC),y)
-OPENCV3_CONF_OPTS += -DCMAKE_CXX_FLAGS="-latomic"
+OPENCV3_CONF_OPTS += -DCMAKE_CXX_FLAGS="$(TARGET_CXXFLAGS) -latomic"
 endif
 
 # OpenCV component options
-- 
2.1.4

[Buildroot] [PATCH] package/opencv3: fix CMAKE_CXX_FLAGS

[Thomas Petazzoni]

Hello,

Adding Samuel in Cc: there is a CMake issue below.

On Wed, 28 Sep 2016 11:40:32 -0700, Max Filippov wrote:
> The commit 4904c4c "package/opencv3: use BR2_TOOLCHAIN_HAS_LIBATOMIC"
> overrides CMAKE_CXX_FLAGS with the single -latomic, losing all ABI
> CFLAGS that are passed there by default. This breaks build on xtensa
> where ABI CFLAGS contain important code generation options.
> 
> Append $(TARGET_CXXFLAGS) to CMAKE_CXX_FLAGS along with -latomic.
> 
> Fixes:
>   http://autobuild.buildroot.net/results/7f1c96abd8fbb5b358a07100ab623316e9bb9dcd
>   http://autobuild.buildroot.net/results/e0c93d0f6d1da0d62d4dbba211a275bfe75e9645
>   http://autobuild.buildroot.net/results/53e7e4b4b6a7b48b8012799d7507f7594dbf01b2
> 
> Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
> ---
>  package/opencv3/opencv3.mk | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/package/opencv3/opencv3.mk b/package/opencv3/opencv3.mk
> index 2529de9..10660a9 100644
> --- a/package/opencv3/opencv3.mk
> +++ b/package/opencv3/opencv3.mk
> @@ -12,7 +12,7 @@ OPENCV3_LICENSE_FILES = LICENSE
>  
>  # Uses __atomic_fetch_add_4
>  ifeq ($(BR2_TOOLCHAIN_HAS_LIBATOMIC),y)
> -OPENCV3_CONF_OPTS += -DCMAKE_CXX_FLAGS="-latomic"
> +OPENCV3_CONF_OPTS += -DCMAKE_CXX_FLAGS="$(TARGET_CXXFLAGS) -latomic"

There is something fishy going on here. Indeed,
support/misc/toolchainfile.cmake.in contains:

  set(CMAKE_CXX_FLAGS "@@TARGET_CXXFLAGS@@ ${CMAKE_CXX_FLAGS}" CACHE STRING "Buildroot CXXFLAGS")

So it should normally always prefix CMAKE_CXX_FLAGS with
TARGET_CXXFLAGS. Can you check the toolchain.cmake file that gets
generated during your build? Does it contains the Xtensa specific
CXXFLAGS ?

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

[Buildroot] [PATCH] package/opencv3: fix CMAKE_CXX_FLAGS

[Max Filippov]

Hi Thomas,

On Thu, Sep 29, 2016 at 2:27 AM, Thomas Petazzoni
<thomas.petazzoni@free-electrons.com> wrote:
> Adding Samuel in Cc: there is a CMake issue below.
>
> On Wed, 28 Sep 2016 11:40:32 -0700, Max Filippov wrote:
>> The commit 4904c4c "package/opencv3: use BR2_TOOLCHAIN_HAS_LIBATOMIC"
>> overrides CMAKE_CXX_FLAGS with the single -latomic, losing all ABI
>> CFLAGS that are passed there by default. This breaks build on xtensa
>> where ABI CFLAGS contain important code generation options.
>>
>> Append $(TARGET_CXXFLAGS) to CMAKE_CXX_FLAGS along with -latomic.
>>
>> Fixes:
>>   http://autobuild.buildroot.net/results/7f1c96abd8fbb5b358a07100ab623316e9bb9dcd
>>   http://autobuild.buildroot.net/results/e0c93d0f6d1da0d62d4dbba211a275bfe75e9645
>>   http://autobuild.buildroot.net/results/53e7e4b4b6a7b48b8012799d7507f7594dbf01b2
>>
>> Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
>> ---
>>  package/opencv3/opencv3.mk | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/package/opencv3/opencv3.mk b/package/opencv3/opencv3.mk
>> index 2529de9..10660a9 100644
>> --- a/package/opencv3/opencv3.mk
>> +++ b/package/opencv3/opencv3.mk
>> @@ -12,7 +12,7 @@ OPENCV3_LICENSE_FILES = LICENSE
>>
>>  # Uses __atomic_fetch_add_4
>>  ifeq ($(BR2_TOOLCHAIN_HAS_LIBATOMIC),y)
>> -OPENCV3_CONF_OPTS += -DCMAKE_CXX_FLAGS="-latomic"
>> +OPENCV3_CONF_OPTS += -DCMAKE_CXX_FLAGS="$(TARGET_CXXFLAGS) -latomic"
>
> There is something fishy going on here. Indeed,
> support/misc/toolchainfile.cmake.in contains:
>
>   set(CMAKE_CXX_FLAGS "@@TARGET_CXXFLAGS@@ ${CMAKE_CXX_FLAGS}" CACHE STRING "Buildroot CXXFLAGS")
>
> So it should normally always prefix CMAKE_CXX_FLAGS with
> TARGET_CXXFLAGS. Can you check the toolchain.cmake file that gets
> generated during your build? Does it contains the Xtensa specific
> CXXFLAGS ?

Yes, it does.
opencv2 which has similar cmake build system but doesn't pass
-DCMAKE_CXX_FLAGS builds correctly.

-- 
Thanks.
-- Max

[Buildroot] [PATCH] package/opencv3: fix CMAKE_CXX_FLAGS

[Thomas Petazzoni]

Hello,

On Thu, 29 Sep 2016 09:14:41 -0700, Max Filippov wrote:

> > There is something fishy going on here. Indeed,
> > support/misc/toolchainfile.cmake.in contains:
> >
> >   set(CMAKE_CXX_FLAGS "@@TARGET_CXXFLAGS@@ ${CMAKE_CXX_FLAGS}" CACHE STRING "Buildroot CXXFLAGS")
> >
> > So it should normally always prefix CMAKE_CXX_FLAGS with
> > TARGET_CXXFLAGS. Can you check the toolchain.cmake file that gets
> > generated during your build? Does it contains the Xtensa specific
> > CXXFLAGS ?  
> 
> Yes, it does.

So if it does, why is your patch necessary? I'm not following here.

Do you mean that the Xtensa-specific flags are present in the
toolchain.cmake file, but are in the end not used during the build ?

> opencv2 which has similar cmake build system but doesn't pass
> -DCMAKE_CXX_FLAGS builds correctly.

OK.

Samuel, can you advise here?

Thanks!

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

[Buildroot] [PATCH] package/opencv3: fix CMAKE_CXX_FLAGS

[Max Filippov]

On Fri, Sep 30, 2016 at 1:10 AM, Thomas Petazzoni
<thomas.petazzoni@free-electrons.com> wrote:
> On Thu, 29 Sep 2016 09:14:41 -0700, Max Filippov wrote:
>> > There is something fishy going on here. Indeed,
>> > support/misc/toolchainfile.cmake.in contains:
>> >
>> >   set(CMAKE_CXX_FLAGS "@@TARGET_CXXFLAGS@@ ${CMAKE_CXX_FLAGS}" CACHE STRING "Buildroot CXXFLAGS")
>> >
>> > So it should normally always prefix CMAKE_CXX_FLAGS with
>> > TARGET_CXXFLAGS. Can you check the toolchain.cmake file that gets
>> > generated during your build? Does it contains the Xtensa specific
>> > CXXFLAGS ?
>>
>> Yes, it does.
>
> So if it does, why is your patch necessary? I'm not following here.
> Do you mean that the Xtensa-specific flags are present in the
> toolchain.cmake file, but are in the end not used during the build ?

Right. The file
  host/usr/share/buildroot/toolchainfile.cmake
exists and contains the following (correct) lines:

set(CMAKE_C_FLAGS "-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
-D_FILE_OFFSET_BITS=64 -mlongcalls -mauto-litpools -Os
${CMAKE_C_FLAGS}" CACHE STRING "Buildroot CFLAGS")
set(CMAKE_CXX_FLAGS "-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
-D_FILE_OFFSET_BITS=64 -mlongcalls -mauto-litpools -Os
${CMAKE_CXX_FLAGS}" CACHE STRING "Buildroot CXXFLAGS")

But the file
  build/opencv3-3.1.0/CMakeCache.txt
that governs opencv3 build contains the following lines:

//Buildroot CXXFLAGS
CMAKE_CXX_FLAGS:STRING=-latomic
//Buildroot CFLAGS
CMAKE_C_FLAGS:STRING='-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
-D_FILE_OFFSET_BITS=64 -mlongcalls -mauto-litpools -Os '

Below is the output that I see during the failing opencv3 build:

--     C++ flags (Release):         -latomic   -fsigned-char -W -Wall
-Werror=return-type -Werror=non-virtual-dtor -Werror=address
-Werror=sequence-point -Wformat -Werror=format-security
-Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow
-Wsign-promo -Wno-narrowing -Wno-delete-non-virtual-dtor
-fdiagnostics-show-option -pthread -fomit-frame-pointer
-ffunction-sections -fvisibility=hidden -fvisibility-inlines-hidden
-O3 -DNDEBUG  -DNDEBUG
--     C++ flags (Debug):           -latomic   -fsigned-char -W -Wall
-Werror=return-type -Werror=non-virtual-dtor -Werror=address
-Werror=sequence-point -Wformat -Werror=format-security
-Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow
-Wsign-promo -Wno-narrowing -Wno-delete-non-virtual-dtor
-fdiagnostics-show-option -pthread -fomit-frame-pointer
-ffunction-sections -fvisibility=hidden -fvisibility-inlines-hidden -g
 -O0 -DDEBUG -D_DEBUG
--     C Compiler:
/home/jcmvbkbc/tmp/br/build-20160928-reproduce-opencv/host/usr/bin/xtensa-linux-gcc
--     C flags (Release):           -D_LARGEFILE_SOURCE
-D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -mlongcalls
-mauto-litpools -Os    -fsigned-char -W -Wall -Werror=return-type
-Werror=non-virtual-dtor -Werror=address -Werror=sequence-point
-Wformat -Werror=format-security -Wmissing-declarations
-Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self
-Wpointer-arith -Wshadow -Wno-narrowing -fdiagnostics-show-option
-pthread -fomit-frame-pointer -ffunction-sections -fvisibility=hidden
-O3 -DNDEBUG  -DNDEBUG
--     C flags (Debug):             -D_LARGEFILE_SOURCE
-D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -mlongcalls
-mauto-litpools -Os    -fsigned-char -W -Wall -Werror=return-type
-Werror=non-virtual-dtor -Werror=address -Werror=sequence-point
-Wformat -Werror=format-security -Wmissing-declarations
-Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self
-Wpointer-arith -Wshadow -Wno-narrowing -fdiagnostics-show-option
-pthread -fomit-frame-pointer -ffunction-sections -fvisibility=hidden
-g  -O0 -DDEBUG -D_DEBUG

Notice the difference between the C and the C++ flags.

-- 
Thanks.
-- Max

[Buildroot] [PATCH] package/opencv3: fix CMAKE_CXX_FLAGS

[Samuel Martin]

Hi all,

On Fri, Sep 30, 2016 at 6:32 PM, Max Filippov <jcmvbkbc@gmail.com> wrote:
> On Fri, Sep 30, 2016 at 1:10 AM, Thomas Petazzoni
> <thomas.petazzoni@free-electrons.com> wrote:
>> On Thu, 29 Sep 2016 09:14:41 -0700, Max Filippov wrote:
>>> > There is something fishy going on here. Indeed,
>>> > support/misc/toolchainfile.cmake.in contains:
>>> >
>>> >   set(CMAKE_CXX_FLAGS "@@TARGET_CXXFLAGS@@ ${CMAKE_CXX_FLAGS}" CACHE STRING "Buildroot CXXFLAGS")
>>> >
>>> > So it should normally always prefix CMAKE_CXX_FLAGS with
>>> > TARGET_CXXFLAGS. Can you check the toolchain.cmake file that gets
>>> > generated during your build? Does it contains the Xtensa specific
>>> > CXXFLAGS ?
>>>
>>> Yes, it does.
>>
>> So if it does, why is your patch necessary? I'm not following here.
>> Do you mean that the Xtensa-specific flags are present in the
>> toolchain.cmake file, but are in the end not used during the build ?
>
> Right. The file
>   host/usr/share/buildroot/toolchainfile.cmake
> exists and contains the following (correct) lines:
>
> set(CMAKE_C_FLAGS "-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
> -D_FILE_OFFSET_BITS=64 -mlongcalls -mauto-litpools -Os
> ${CMAKE_C_FLAGS}" CACHE STRING "Buildroot CFLAGS")
> set(CMAKE_CXX_FLAGS "-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
> -D_FILE_OFFSET_BITS=64 -mlongcalls -mauto-litpools -Os
> ${CMAKE_CXX_FLAGS}" CACHE STRING "Buildroot CXXFLAGS")
>
> But the file
>   build/opencv3-3.1.0/CMakeCache.txt
> that governs opencv3 build contains the following lines:
>
> //Buildroot CXXFLAGS
> CMAKE_CXX_FLAGS:STRING=-latomic
> //Buildroot CFLAGS
> CMAKE_C_FLAGS:STRING='-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
> -D_FILE_OFFSET_BITS=64 -mlongcalls -mauto-litpools -Os '
>
> Below is the output that I see during the failing opencv3 build:
>
> --     C++ flags (Release):         -latomic   -fsigned-char -W -Wall
> -Werror=return-type -Werror=non-virtual-dtor -Werror=address
> -Werror=sequence-point -Wformat -Werror=format-security
> -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow
> -Wsign-promo -Wno-narrowing -Wno-delete-non-virtual-dtor
> -fdiagnostics-show-option -pthread -fomit-frame-pointer
> -ffunction-sections -fvisibility=hidden -fvisibility-inlines-hidden
> -O3 -DNDEBUG  -DNDEBUG
> --     C++ flags (Debug):           -latomic   -fsigned-char -W -Wall
> -Werror=return-type -Werror=non-virtual-dtor -Werror=address
> -Werror=sequence-point -Wformat -Werror=format-security
> -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow
> -Wsign-promo -Wno-narrowing -Wno-delete-non-virtual-dtor
> -fdiagnostics-show-option -pthread -fomit-frame-pointer
> -ffunction-sections -fvisibility=hidden -fvisibility-inlines-hidden -g
>  -O0 -DDEBUG -D_DEBUG
> --     C Compiler:
> /home/jcmvbkbc/tmp/br/build-20160928-reproduce-opencv/host/usr/bin/xtensa-linux-gcc
> --     C flags (Release):           -D_LARGEFILE_SOURCE
> -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -mlongcalls
> -mauto-litpools -Os    -fsigned-char -W -Wall -Werror=return-type
> -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point
> -Wformat -Werror=format-security -Wmissing-declarations
> -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self
> -Wpointer-arith -Wshadow -Wno-narrowing -fdiagnostics-show-option
> -pthread -fomit-frame-pointer -ffunction-sections -fvisibility=hidden
> -O3 -DNDEBUG  -DNDEBUG
> --     C flags (Debug):             -D_LARGEFILE_SOURCE
> -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -mlongcalls
> -mauto-litpools -Os    -fsigned-char -W -Wall -Werror=return-type
> -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point
> -Wformat -Werror=format-security -Wmissing-declarations
> -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self
> -Wpointer-arith -Wshadow -Wno-narrowing -fdiagnostics-show-option
> -pthread -fomit-frame-pointer -ffunction-sections -fvisibility=hidden
> -g  -O0 -DDEBUG -D_DEBUG
>
> Notice the difference between the C and the C++ flags.

Indeed, there is a bug in the way we are currently setting/expending
{C,CXX}FLAGS in the CMake toolchain file.
I'll post a patch fixing it quickly.

Regards,

-- 
Samuel

[Buildroot] [PATCH] package/opencv3: fix CMAKE_CXX_FLAGS

[Vicente Olivert Riera]

Hello,

since this patch has been included [1] in Samuel's series I'm marking it
as superseded in patchwork.

1: https://patchwork.ozlabs.org/patch/682674/

Regards,

Vincent.

On 01/10/16 00:07, Samuel Martin wrote:
> Hi all,
> 
> On Fri, Sep 30, 2016 at 6:32 PM, Max Filippov <jcmvbkbc@gmail.com> wrote:
>> On Fri, Sep 30, 2016 at 1:10 AM, Thomas Petazzoni
>> <thomas.petazzoni@free-electrons.com> wrote:
>>> On Thu, 29 Sep 2016 09:14:41 -0700, Max Filippov wrote:
>>>>> There is something fishy going on here. Indeed,
>>>>> support/misc/toolchainfile.cmake.in contains:
>>>>>
>>>>>   set(CMAKE_CXX_FLAGS "@@TARGET_CXXFLAGS@@ ${CMAKE_CXX_FLAGS}" CACHE STRING "Buildroot CXXFLAGS")
>>>>>
>>>>> So it should normally always prefix CMAKE_CXX_FLAGS with
>>>>> TARGET_CXXFLAGS. Can you check the toolchain.cmake file that gets
>>>>> generated during your build? Does it contains the Xtensa specific
>>>>> CXXFLAGS ?
>>>>
>>>> Yes, it does.
>>>
>>> So if it does, why is your patch necessary? I'm not following here.
>>> Do you mean that the Xtensa-specific flags are present in the
>>> toolchain.cmake file, but are in the end not used during the build ?
>>
>> Right. The file
>>   host/usr/share/buildroot/toolchainfile.cmake
>> exists and contains the following (correct) lines:
>>
>> set(CMAKE_C_FLAGS "-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
>> -D_FILE_OFFSET_BITS=64 -mlongcalls -mauto-litpools -Os
>> ${CMAKE_C_FLAGS}" CACHE STRING "Buildroot CFLAGS")
>> set(CMAKE_CXX_FLAGS "-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
>> -D_FILE_OFFSET_BITS=64 -mlongcalls -mauto-litpools -Os
>> ${CMAKE_CXX_FLAGS}" CACHE STRING "Buildroot CXXFLAGS")
>>
>> But the file
>>   build/opencv3-3.1.0/CMakeCache.txt
>> that governs opencv3 build contains the following lines:
>>
>> //Buildroot CXXFLAGS
>> CMAKE_CXX_FLAGS:STRING=-latomic
>> //Buildroot CFLAGS
>> CMAKE_C_FLAGS:STRING='-D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE
>> -D_FILE_OFFSET_BITS=64 -mlongcalls -mauto-litpools -Os '
>>
>> Below is the output that I see during the failing opencv3 build:
>>
>> --     C++ flags (Release):         -latomic   -fsigned-char -W -Wall
>> -Werror=return-type -Werror=non-virtual-dtor -Werror=address
>> -Werror=sequence-point -Wformat -Werror=format-security
>> -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow
>> -Wsign-promo -Wno-narrowing -Wno-delete-non-virtual-dtor
>> -fdiagnostics-show-option -pthread -fomit-frame-pointer
>> -ffunction-sections -fvisibility=hidden -fvisibility-inlines-hidden
>> -O3 -DNDEBUG  -DNDEBUG
>> --     C++ flags (Debug):           -latomic   -fsigned-char -W -Wall
>> -Werror=return-type -Werror=non-virtual-dtor -Werror=address
>> -Werror=sequence-point -Wformat -Werror=format-security
>> -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow
>> -Wsign-promo -Wno-narrowing -Wno-delete-non-virtual-dtor
>> -fdiagnostics-show-option -pthread -fomit-frame-pointer
>> -ffunction-sections -fvisibility=hidden -fvisibility-inlines-hidden -g
>>  -O0 -DDEBUG -D_DEBUG
>> --     C Compiler:
>> /home/jcmvbkbc/tmp/br/build-20160928-reproduce-opencv/host/usr/bin/xtensa-linux-gcc
>> --     C flags (Release):           -D_LARGEFILE_SOURCE
>> -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -mlongcalls
>> -mauto-litpools -Os    -fsigned-char -W -Wall -Werror=return-type
>> -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point
>> -Wformat -Werror=format-security -Wmissing-declarations
>> -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self
>> -Wpointer-arith -Wshadow -Wno-narrowing -fdiagnostics-show-option
>> -pthread -fomit-frame-pointer -ffunction-sections -fvisibility=hidden
>> -O3 -DNDEBUG  -DNDEBUG
>> --     C flags (Debug):             -D_LARGEFILE_SOURCE
>> -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -mlongcalls
>> -mauto-litpools -Os    -fsigned-char -W -Wall -Werror=return-type
>> -Werror=non-virtual-dtor -Werror=address -Werror=sequence-point
>> -Wformat -Werror=format-security -Wmissing-declarations
>> -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self
>> -Wpointer-arith -Wshadow -Wno-narrowing -fdiagnostics-show-option
>> -pthread -fomit-frame-pointer -ffunction-sections -fvisibility=hidden
>> -g  -O0 -DDEBUG -D_DEBUG
>>
>> Notice the difference between the C and the C++ flags.
> 
> Indeed, there is a bug in the way we are currently setting/expending
> {C,CXX}FLAGS in the CMake toolchain file.
> I'll post a patch fixing it quickly.
> 
> Regards,
>