Add a minimal linux build target for Travis

[extended tests]
Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9888)

.travis.yml

@@ -132,6 +132,9 @@ matrix:
             # exit-zero treats all errors as warnings.  The GitHub editor is 127 chars wide
             - flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
           script: true
+        - os: linux
+          compiler: gcc
+          env: EXTENDED_TEST="yes" CONFIGURE_TARGET="linux-generic32" CONFIG_OPTS="--strict-warnings no-shared no-dso no-pic no-autoload-config no-engine no-comp no-cms no-dh no-dsa no-ec2m no-srp no-des no-mdc2 no-md4 no-rc2 no-rc4 no-bf no-camellia no-cast no-idea no-seed no-whirlpool no-ocsp no-sm2 no-sm3 no-sm4 no-ssl3 no-ssl3-method no-psk no-heartbeats no-nextprotoneg no-sctp no-srtp no-asm -DOPENSSL_SMALL_FOOTPRINT"
     exclude:
         - os: linux
           compiler: clang
@@ -175,7 +178,11 @@ before_script:
           elif which ccache >/dev/null; then
               CC="ccache $CC";
           fi;
-          $srcdir/config -v $CONFIG_OPTS;
+          if [ -n "$CONFIGURE_TARGET" ]; then
+              $srcdir/Configure $CONFIGURE_TARGET $CONFIG_OPTS;
+          else
+              $srcdir/config -v $CONFIG_OPTS;
+          fi;
       fi
     - ./configdata.pm --dump
     - cd $top