Enable GCC warnings in developer builds

However, do not fail; just issue the warnings.  Add an option
--enable-gcc-warnings=warn-only to configure, to implement this.
* INSTALL, etc/NEWS: Document this.
* configure.ac (gl_GCC_VERSION_IFELSE): New macro, from coreutils.
(gl_gcc_warnings, WERROR_CFLAGS): Use it to add new option.
Don’t treat --with-x-toolkit=no as a special case when configuring
warnings.

1 files changed, 6 insertions, 0 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 6cc1c5ae01c..d38bc3d9099 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -25,6 +25,12 @@ otherwise leave it unmarked.
 
 * Installation Changes in Emacs 25.2
 
+** The new option 'configure --enable-gcc-warnings=warn-only' causes
+GCC to issue warnings without stopping the bild.  This behavior is now
+the default in developer builds.  As before, use
+'--disable-gcc-warnings' to suppress GCC's warnings, and
+'--enable-gcc-warnings' to stop the build if GCC issues warnings.
+
 +++
 ** New configure option '--disable-build-details' attempts to build an
 Emacs that is more likely to be reproducible; that is, if you build