[ci] Remove unnecessary warning declarations

clang -Weverything still left to be ported to pragmas
diff --git a/.circleci/config.yml b/.circleci/config.yml
index db76361..6a01e54 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -90,7 +90,7 @@
       - run: pip install flake8 fonttools
       - run: flake8 . --count --select=E901,E999,F821,F822,F823 --show-source --statistics
       # C??FLAGS are not needed for a regular build
-      - run: CFLAGS="-Wall -Wextra -Wno-cast-function-type" CXXFLAGS="-Wall -Wextra -Wno-unused-parameter -Wno-missing-field-initializers -Wno-class-memaccess -Wpedantic -Wno-format -Wno-cast-function-type" ./autogen.sh --with-freetype --with-glib --with-gobject --with-cairo --with-icu --with-graphite2
+      - run: ./autogen.sh --with-freetype --with-glib --with-gobject --with-cairo --with-icu --with-graphite2
       - run: make -j32 CPPFLAGS="-Werror"
       - run: make check CPPFLAGS="-Werror" || .ci/fail.sh