Merge branch 'maint-0.2.9' into maint-0.3.5

Merge C_DIALECT_OPTIONS from ticket32500_029 with
other configure options from maint-0.3.5.

diff --cc .travis.yml
index 7f0e785876befe84f3213ec317407cc80f5d4c5e,51368ea5120eb5685d6a8714e3bd8645455ce7a8..f227321876a1c264f092b6f8b098ecb8f8cbb390
--- 1/.travis.yml
--- 2/.travis.yml
+++ b/.travis.yml
@@@ -39,12 -32,12 +39,16 @@@ matrix
      ## We run basic tests on macOS
      - compiler: clang
        os: osx
+       ## Turn off some newer features, turn on clang's -Wtypedef-redefinition
+       env: C_DIALECT_OPTIONS="-std=gnu99"
 +    ## We check NSS
 +    ## NSS is a fast job, clang is slower on Linux, so we do NSS clang
 +    - env: NSS_OPTIONS="--enable-nss"
 +      compiler: clang
      ## We run chutney on Linux, because it's faster than chutney on macOS
-     - env: CHUTNEY="yes" CHUTNEY_ALLOW_FAILURES="2" SKIP_MAKE_CHECK="yes"
+     ## Use -std=gnu99 to turn off some newer features, and maybe turn on some
+     ## extra gcc warnings?
+     - env: CHUTNEY="yes" CHUTNEY_ALLOW_FAILURES="2" SKIP_MAKE_CHECK="yes" C_DIALECT_OPTIONS="-std=gnu99"
        ## (Linux only) Use an older Linux image (Ubuntu Trusty)
        ## The Xenial and Bionic images cause permissions issues for chutney,
        ## this is a workaround, until we fix #32240.
@@@ -195,16 -136,12 +199,16 @@@ install
    - python --version
    ## If we're running chutney, show the chutney commit
    - if [[ "$CHUTNEY" != "" ]]; then pushd "$CHUTNEY_PATH"; git log -1 ; popd ; fi
 +  ## If we're running stem, show the stem version and commit
 +  - if [[ "$TEST_STEM" != "" ]]; then pushd stem; python -c "from stem import stem; print(stem.__version__);"; git log -1; popd; fi
  
  script:
 +  # Skip test_rebind on macOS
 +  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then export TOR_SKIP_TEST_REBIND=true; fi
    - ./autogen.sh
 -  - CONFIGURE_FLAGS="$ASCIIDOC_OPTIONS $COVERAGE_OPTIONS $HARDENING_OPTIONS $OPENSSL_OPTIONS --enable-fatal-warnings --disable-silent-rules"
 +  - CONFIGURE_FLAGS="$ASCIIDOC_OPTIONS $COVERAGE_OPTIONS $HARDENING_OPTIONS $MODULES_OPTIONS $NSS_OPTIONS $OPENSSL_OPTIONS $RUST_OPTIONS --enable-fatal-warnings --disable-silent-rules"
-   - echo "Configure flags are $CONFIGURE_FLAGS"
-   - ./configure $CONFIGURE_FLAGS
+   - echo "Configure flags are $CONFIGURE_FLAGS CC=\"$CC $C_DIALECT_OPTIONS\""
+   - ./configure $CONFIGURE_FLAGS CC="$CC $C_DIALECT_OPTIONS"
    ## We run `make check` because that's what https://jenkins.torproject.org does.
    - if [[ "$SKIP_MAKE_CHECK" == "" ]]; then make check; fi
    - if [[ "$DISTCHECK" != "" ]]; then make distcheck DISTCHECK_CONFIGURE_FLAGS="$CONFIGURE_FLAGS"; fi