Do a strict ./configure --enable-developer build to make warnings errors in CI

This will make it harder to commit code that triggers warnings.

This list of allowed warnings is too long, but can be trimmed down
over time.

Signed-off-by: Andrew Bartlett <abartlet@samba.org>

.travis.yml

@@ -42,7 +42,12 @@ install:
                   --with-berkeley-db \
                   --with-berkeley-db-include=/usr/local/opt/berkeley-db/include
       else
-          ../configure --srcdir=`dirname "$PWD"` --enable-maintainer-mode $COVERAGE
+          # This list of -Wno-error options should be reduced over time where possible
+          if [ x"$TRAVIS_COMPILER" != x"clang" ]; then
+              CFLAGS="-Wno-error=empty-body -Wno-error=shadow -Wno-error=unused-value -Wno-error=unused-but-set-variable -Wno-error=bad-function-cast -Wno-error=unused-function -Wno-error=unused-result -Wno-error=deprecated-declarations" ../configure --enable-developer --srcdir=`dirname "$PWD"` --enable-maintainer-mode $COVERAGE
+          else
+              CFLAGS="-Wno-error=shadow -Wno-error=bad-function-cast -Wno-error=unused-function -Wno-error=unused-result -Wno-error=deprecated-declarations" ../configure --enable-developer --srcdir=`dirname "$PWD"` --enable-maintainer-mode $COVERAGE
+          fi
       fi
     - ulimit -c unlimited; make -j3