disable -Werror in configure file

Question

While making a project with Makefile, I get this error:

error: implicit declaration of function ‘fatal’ [-Werror=implicit-function-declaration]

cc1: all warnings being treated as errors

The ./configure --help shows

Optional Features:
  --disable-option-checking  ignore unrecognized --enable/--with options
  --disable-FEATURE       do not include FEATURE (same as --enable-FEATURE=no)
  --enable-FEATURE[=ARG]  include FEATURE [ARG=yes]
  --disable-dependency-tracking  speeds up one-time build
  --enable-dependency-tracking   do not reject slow dependency extractors
  --disable-gtktest       do not try to compile and run a test GTK+ program
  --enable-debug    Turn on debugging

how can I tell configure not to include -Werror??

Answer 1

Werror is a gcc argument, you cannot remove it directly via ./configure, otherwise an option like --disable-error would show up in the help text. However, it's possible.

Set an environment variable:

export CFLAGS="-Wno-error"

That's for for C compilers. If the project uses C++, do:

export CXXFLAGS="-Wno-error"

In the very rare case the project does not honor this variables, your last resort is to edit the configure.ac file and search for -Werror and remove it from the string it occurs in (be careful though).

Answer 2

it seems like the feature has been in autotools for many years:

./configure --disable-werror

unfortunately, i wasn't able to get the following specific case to work:

./configure --enable-wno-error=unused-value

maybe it could work if one escaped '=' symbol, assuming it's possible. Like skim says, one can still use CFLAGS or CXXFLAGS.