libvisual/configure.ac: Add -Werror on CI=true

Author: hartwork

libvisual/configure.ac

@@ -520,6 +520,14 @@ OPT_CFLAGS="-mwindows"
 fi
 AC_SUBST(OPT_CFLAGS)
 
+AS_IF([test "x${CI}" = xtrue], [
+  CFLAGS="${CFLAGS} -Werror"
+  CFLAGS="${CFLAGS} -Wno-error=missing-prototypes"  # TODO: drop line after fixing!
+  CFLAGS="${CFLAGS} -Wno-error=return-type"  # TODO: drop line after fixing!
+  CFLAGS="${CFLAGS} -Wno-error=uninitialized"  # TODO: drop line after fixing!
+  CFLAGS="${CFLAGS} -Wno-error=unused-function"  # TODO: drop line after fixing!
+])
+
 AC_SUBST(CFLAGS, "${CFLAGS} ${DEBUG_CFLAGS} ${OPT_CFLAGS}")
 
 libs_dynamic_loader="-ldl"