Remove -ftree-vectorizer-verbose=0 option notrecognized by MaxOS/X c… (#4412)

…ompiler

## Problem

## Summary of changes

## Checklist before requesting a review

- [ ] I have performed a self-review of my code.
- [ ] If it is a core feature, I have added thorough tests.
- [ ] Do we need to implement analytics? if so did you add the relevant
metrics to the dashboard?
- [ ] If this PR requires public announcement, mark it with
/release-notes label and add several sentences in this section.

## Checklist before merging

- [ ] Do not forget to reformat commit message to not include the above
checklist

pgxn/hnsw/Makefile

@@ -12,7 +12,7 @@ REGRESS_OPTS = --inputdir=test --load-extension=hnsw
 # For auto-vectorization:
 # - GCC (needs -ftree-vectorize OR -O3) - https://gcc.gnu.org/projects/tree-ssa/vectorization.html
 PG_CFLAGS += -O3
-PG_CPPFLAGS +=  -msse4.1 -O3 -march=native -ftree-vectorize -ftree-vectorizer-verbose=0
+PG_CXXFLAGS +=  -msse4 -mavx2 -O3 -std=c++11
 PG_LDFLAGS += -lstdc++
 
 all: $(EXTENSION)--$(EXTVERSION).sql