silence compiler warnings for RHEL 9 Linux

We updated ${CSILENCE} Makefile variables for entries in an attempt to
minimize compiler warnings.  This was tested using
gcc version 11.4.1 20230605 (Red Hat 11.4.1-2) (GCC).

TODO: Recheck macOS clang to see if any new warnings have occur
      under macOS clang.

2018/hou/Makefile

@@ -84,7 +84,8 @@ CC= cc
 ifeq "$(findstring $(CLANG),${CC})" "$(CLANG)"
 #
 CSILENCE+= -Wno-float-conversion -Wno-format-nonliteral -Wno-missing-prototypes \
-	-Wno-poison-system-directories -Wno-strict-prototypes
+	   -Wno-poison-system-directories -Wno-strict-prototypes \
+	   -Wno-implicit-int-float-conversion -Wno-shorten-64-to-32
 #
 CWARN+= -Weverything
 #