[Buildroot] [PATCH] Set CFLAGS = $(TARGET_CFLAGS) for many packages

[Buildroot] [PATCH] Set CFLAGS = $(TARGET_CFLAGS) for many packages

[Ulf Samuelsson]

If you make Buildroot from scratch, CFLAGS gets set during the build,
but if you add packages later, then CFLAGS should be set in the
makefile fragment of the new package.

I believe that TARGET_CFLAGS needs to include the Linux Include
Directory or you will get compolie time errors.
Don't have a clean patch for that yet, but this is what I do:

TARGET_CFLAGS=$(TARGET_OPTIMIZATION) $(TARGET_DEBUGGING)

should be changed to

TARGET_CFLAGS=$(TARGET_OPTIMIZATION) $(TARGET_DEBUGGING) \
	-I$(TOOL_BUILD_DIR)/linux/include


Best Regards
Ulf Samuelsson

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[Buildroot] [PATCH] Set CFLAGS = $(TARGET_CFLAGS) for many packages

[Bernhard Fischer]

On Wed, Jan 24, 2007 at 12:53:53AM +0100, Ulf Samuelsson wrote:
>If you make Buildroot from scratch, CFLAGS gets set during the build,
>but if you add packages later, then CFLAGS should be set in the
>makefile fragment of the new package.

I don't understand what you mean here. Please elaborate
>
>I believe that TARGET_CFLAGS needs to include the Linux Include
>Directory or you will get compolie time errors.

I don't have the linux include in my TARGET_CFLAGS AFAIK and do not get
compile errors. What kernel-headers are you using? What errors are you
seeing with what package?

[Buildroot] [PATCH] Set CFLAGS = $(TARGET_CFLAGS) for many packages

[Ulf Samuelsson]

Bernhard Fischer wrote:
> On Wed, Jan 24, 2007 at 12:53:53AM +0100, Ulf Samuelsson wrote:
>> If you make Buildroot from scratch, CFLAGS gets set during the build,
>> but if you add packages later, then CFLAGS should be set in the
>> makefile fragment of the new package.
>
> I don't understand what you mean here. Please elaborate
>>

Some packages require kernel headers.
If you build from scratch, something sets CFLAGS to a good value.

If you come back the next day, reconfigure your system,
to include a new package, and recompile, many packages
will bomb out because they do not find the "asm-generic.h"

By adding this CFLAGS patch you can compile those packages.

Many packages have this already, many don't.
Can you explain when you have it and when you don't?

>> I believe that TARGET_CFLAGS needs to include the Linux Include
>> Directory or you will get compolie time errors.
>
> I don't have the linux include in my TARGET_CFLAGS AFAIK and do not
> get compile errors. What kernel-headers are you using? What errors
> are you seeing with what package?

Best Regards,
Ulf Samuelsson
ulf at atmel.com
GSM:  +46 (706) 22 44 57
Tel:     +46  (8) 441 54 22
Fax:     +46 (8) 441 54 29
Mail: Box 2033  174 02 Sundbyberg
Visit: Kavalleriv?gen 24
          174 58 Sundbyberg'
Sweden

[Buildroot] [PATCH] Set CFLAGS = $(TARGET_CFLAGS) for many packages

[Bernhard Fischer]

On Thu, Jan 25, 2007 at 01:02:49AM +0100, Ulf Samuelsson wrote:
>Bernhard Fischer wrote:
>>On Wed, Jan 24, 2007 at 12:53:53AM +0100, Ulf Samuelsson wrote:
>>>If you make Buildroot from scratch, CFLAGS gets set during the build,
>>>but if you add packages later, then CFLAGS should be set in the
>>>makefile fragment of the new package.
>>
>>I don't understand what you mean here. Please elaborate
>>>
>
>Some packages require kernel headers.

The few packages that really need kernel-internal or any other
non-standard include path have to specify their include manually. 

>If you build from scratch, something sets CFLAGS to a good value.
>
>If you come back the next day, reconfigure your system,
>to include a new package, and recompile, many packages
>will bomb out because they do not find the "asm-generic.h"

I cannot reproduce this. Can you paste an error and describe how i can
reproduce this, locally?

>By adding this CFLAGS patch you can compile those packages.
>
>Many packages have this already, many don't.
>Can you explain when you have it and when you don't?

See above. If a package needs any headers that do not live in a standard
place (see e.g. gmp/mpfr.h for gcc or openswan that has a broken
makefile in this respect) have to specify that explicitely.

>>>I believe that TARGET_CFLAGS needs to include the Linux Include
>>>Directory or you will get compolie time errors.
>>
>>I don't have the linux include in my TARGET_CFLAGS AFAIK and do not
>>get compile errors. What kernel-headers are you using? What errors
>>are you seeing with what package?

Please provide an example.

for me, e.g., my cross-compiler works. What do you see if you do the
equivalent thing?

$ echo "#include <asm/unistd.h>" | \
/scratch/obj.x86_64/buildroot.mine/build_i586/staging_dir/bin/i586-linux-gcc \
-xc -dD -E - | grep unistd
# 1 "/scratch/obj.x86_64/buildroot.mine/build_i586/staging_dir/lib/gcc/i586-linux-uclibc/4.2.0/../../../../i586-linux-uclibc/sys-include/asm/unistd.h" 1 3 4

[Buildroot] [PATCH] Set CFLAGS = $(TARGET_CFLAGS) for many packages

[Ulf Samuelsson]

Bernhard Fischer wrote:
> On Thu, Jan 25, 2007 at 01:02:49AM +0100, Ulf Samuelsson wrote:
>> Bernhard Fischer wrote:
>>> On Wed, Jan 24, 2007 at 12:53:53AM +0100, Ulf Samuelsson wrote:
>>>> If you make Buildroot from scratch, CFLAGS gets set during the
>>>> build, but if you add packages later, then CFLAGS should be set in
>>>> the makefile fragment of the new package.
>>> 
>>> I don't understand what you mean here. Please elaborate
>>>> 
>> 
>> Some packages require kernel headers.
> 
> The few packages that really need kernel-internal or any other
> non-standard include path have to specify their include manually.
> 
>> If you build from scratch, something sets CFLAGS to a good value.
>> 
>> If you come back the next day, reconfigure your system,
>> to include a new package, and recompile, many packages
>> will bomb out because they do not find the "asm-generic.h"
> 
> I cannot reproduce this. Can you paste an error and describe how i can
> reproduce this, locally?
> 
>> By adding this CFLAGS patch you can compile those packages.
>> 
>> Many packages have this already, many don't.
>> Can you explain when you have it and when you don't?
> 
> See above. If a package needs any headers that do not live in a
> standard 
> place (see e.g. gmp/mpfr.h for gcc or openswan that has a broken
> makefile in this respect) have to specify that explicitely.
> 
>>>> I believe that TARGET_CFLAGS needs to include the Linux Include
>>>> Directory or you will get compolie time errors.
>>> 
>>> I don't have the linux include in my TARGET_CFLAGS AFAIK and do not
>>> get compile errors. What kernel-headers are you using? What errors
>>> are you seeing with what package?
> 


As I mentioned yesterday, I have not been able to reproduce the failure
to build due to lack of Linux/include, 
but the patch I sent does not add anything to TARGET_CFLAGS.

The patch is only making sure that each package listed is compiled
with  CFLAGS=$(TARGET_CFLAGS).

Since the current buildroot does not use $(TARGET_CFLAGS)
when compiling these package the optimization level and debug level
specified in the ".config" file gets ignored.

If this is correct behaviour, then I am confused.
Is there a golden rule, which packages should apply TARGET_CFLAGS 
and which packages should not?

Best Regards,
Ulf Samuelsson