workflows: exclude librdkafka-dev from pr-compile-without-cxx

Upstream is not really amused with the proposal to allow compilation
without CXX support, see confluentinc/librdkafka#4366.
So disable it from the check for now.

Signed-off-by: Thomas Devoogdt <[email protected]>

Author: ThomasDevoogdt

.github/workflows/pr-compile-check.yaml

@@ -139,6 +139,6 @@ jobs:
         run: |
           export CXX=/bin/false
           export nparallel=$(( $(getconf _NPROCESSORS_ONLN) > 8 ? 8 : $(getconf _NPROCESSORS_ONLN) ))
-          cmake -DPREFER_SYSTEM_LIB_ZSTD=ON ../
+          cmake -DPREFER_SYSTEM_LIB_ZSTD=ON -DFLB_KAFKA=OFF ../
           make -j $nparallel
         working-directory: build