How to disable -Werror=date-time/macro “__DATE__” might prevent reproducible builds

Question

I am trying to compile a driver for a Netis WF2190 adapter. Yes, I just downloaded the latest from them.

How can I disable the -Werror=date-time in the build? I can't find it anywhere in the build script so I figure it must be some global default setting. Clearly the code is just trying to embed the build date/time into the output, so there should be no problem with disabling this warning.

Here are some of the warnings I'm getting treated as errors:

/home/andy/RTL8812AU_linux_v4.3.8_12175.20140902/driver/rtl8812AU_linux_v4.3.8_12175.20140902/core/rtw_debug.c:66:1: error: macro "__DATE__" might prevent reproducible builds [-Werror=date-time]
/home/andy/RTL8812AU_linux_v4.3.8_12175.20140902/driver/rtl8812AU_linux_v4.3.8_12175.20140902/core/rtw_debug.c:66:1: error: macro "__TIME__" might prevent reproducible builds [-Werror=date-time]
cc1: some warnings being treated as errors

Answer 1

The date-time warning is new in gcc 4.9 I think - it is possibly turned on implicitly by -Wall (and turned into an error implicitly by -Werror).

You could try turning it off explicitly using the -Wno- form i.e. by adding

-Wno-error=date-time 

to the CFLAGS.

Answer 2

I tried quite a few times adding the "Wno-error=date-time" line to the CFLAGS, but it didn't seem to work.

The easiest solution by far for me was to find the file that was producing the "__DATE__" line by executing

grep -r "__DATE__"

which (for the source code that I'm working with) gave me the file

acore/info.patch:+          "Compiled on " __DATE__ " for kernel %s"

I simply changed this to a string without the variable by removing the quotation marks, i.e.

"Compiled on __DATE__ for kernel %s"

The compilation was then able to proceed

EDIT: As mentioned before, use make clean before running configure and make, or even better, extract a fresh version from the zip/tar file

Answer 3

It might be better to remove the offending macro by deleting line 66 from the rtw_debug.c file.

sed -i -e '66d' /home/andy/RTL8812AU_linux_v4.3.8_12175.20140902/driver/rtl8812AU_linux_v4.3.8_12175.20140902/core/rtw_debug.c

Now you can continue with the build:

cd /home/andy/RTL8812AU_linux_v4.3.8_12175.20140902/
sudo make clean
make
sudo make install