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.

2000/robison/Makefile

@@ -38,9 +38,10 @@ include ../../var.mk
 
 # Common C compiler warnings to silence
 #
-CSILENCE= -Wno-bitwise-op-parentheses -Wno-error -Wno-implicit-function-declaration \
-	-Wno-format-security -Wno-parentheses -Wno-shift-negative-value \
-	-Wno-shift-op-parentheses -Wno-strict-prototypes
+CSILENCE= -Wno-bitwise-op-parentheses -Wno-error \
+	  -Wno-implicit-function-declaration -Wno-format-security \
+	  -Wno-parentheses -Wno-shift-negative-value -Wno-shift-op-parentheses \
+	  -Wno-strict-prototypes -Wno-maybe-uninitialized
 
 # Common C compiler warning flags
 #
@@ -86,9 +87,10 @@ CC= cc
 ifeq "$(findstring $(CLANG),${CC})" "$(CLANG)"
 #
 CSILENCE+= -Wno-comma -Wno-conditional-uninitialized -Wno-format-nonliteral \
-	-Wno-implicit-int-conversion -Wno-missing-prototypes \
-	-Wno-missing-variable-declarations -Wno-poison-system-directories \
-	-Wno-shadow -Wno-sign-conversion
+	   -Wno-implicit-int-conversion -Wno-missing-prototypes \
+	   -Wno-missing-variable-declarations -Wno-poison-system-directories \
+	   -Wno-unknown-warning-option -Wno-unsafe-buffer-usage \
+	   -Wno-shadow -Wno-sign-conversion
 #
 CWARN+= -Weverything
 #