silence compiler warnings for macOS

After silencing compiler warnings for RHEL 9 Linux,
we silence the result on macOS for
Apple clang version 15.0.0 (clang-1500.3.9.4).

2018/bellard/Makefile

@@ -41,7 +41,8 @@ include ../../var.mk
 CSILENCE= -Wno-error -Wno-implicit-function-declaration -Wno-implicit-int \
 	  -Wno-logical-op-parentheses -Wno-main -Wno-parentheses -Wno-pedantic \
 	  -Wno-return-type -Wno-shift-op-parentheses -Wno-builtin-declaration-mismatch \
-	  -Wno-deprecated-non-prototype -Wno-unused-parameter
+	  -Wno-deprecated-non-prototype -Wno-unused-parameter \
+	  -Wno-unknown-warning-option
 
 # Common C compiler warning flags
 #

2018/burton1/Makefile

@@ -40,7 +40,8 @@ include ../../var.mk
 #
 CSILENCE= -Wno-char-subscripts -Wno-error -Wno-implicit-function-declaration \
 	  -Wno-implicit-int -Wno-main -Wno-deprecated-non-prototype \
-	  -Wno-builtin-declaration-mismatch -Wno-unused-value
+	  -Wno-builtin-declaration-mismatch -Wno-unused-value \
+	  -Wno-unknown-warning-option
 
 # Common C compiler warning flags
 #

2018/ferguson/Makefile

@@ -38,7 +38,7 @@ include ../../var.mk
 
 # Common C compiler warnings to silence
 #
-CSILENCE= -Wno-strict-prototypes -Wno-stringop-truncation
+CSILENCE= -Wno-strict-prototypes -Wno-stringop-truncation -Wno-unknown-warning-option
 
 # Common C compiler warning flags
 #

2018/vokes/Makefile

@@ -85,7 +85,7 @@ ifeq "$(findstring $(CLANG),${CC})" "$(CLANG)"
 #
 CSILENCE+= -Wno-missing-prototypes -Wno-poison-system-directories \
 	   -Wno-strict-prototypes -Wno-incompatible-function-pointer-types-strict \
-	   -Wno-unsafe-buffer-usage
+	   -Wno-unsafe-buffer-usage -Wno-unknown-warning-option
 #
 CWARN+= -Weverything
 #