travis BUGFIX calling clang in sudo

Travis installs clang into directories available only via login shell
(not just via environment as tried in previous commit), so sudo must be
invoked with -i option in case the command needs clang as in the case of
building libpcre2.
diff --git a/.travis.yml b/.travis.yml
index 6dc1091..cd71dd8 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -60,7 +60,7 @@
         - cd cmocka-1.1.2 && mkdir build && cd build && cmake .. && make -j2 && sudo make install && cd ../..
         - wget https://ftp.pcre.org/pub/pcre/pcre2-10.30.tar.gz
         - tar -xzf pcre2-10.30.tar.gz
-        - cd pcre2-10.30 && ./configure && make -j2 && sudo -E make install && cd ..
+        - cd pcre2-10.30 && ./configure && make -j2 && sudo -i make install && cd ..
       script:
         - mkdir build && cd build && cmake .. && make -j2 && ctest --output-on-failure && cd -
     - stage: Test