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).

2013/birken/Makefile

@@ -39,7 +39,7 @@ include ../../var.mk
 # Common C compiler warnings to silence
 #
 CSILENCE= -Wno-newline-eof -Wno-strict-prototypes -Wno-maybe-uninitialized \
-	  -Wno-misleading-indentation
+	  -Wno-misleading-indentation -Wno-unknown-warning-option
 
 # Common C compiler warning flags
 #

2013/cable3/Makefile

@@ -97,7 +97,8 @@ CSILENCE+= -Wno-cast-align -Wno-comma -Wno-dollar-in-identifier-extension \
 	   -Wno-poison-system-directories -Wno-shadow -Wno-sign-conversion \
 	   -Wno-strict-prototypes -Wno-shorten-64-to-32 \
 	   -Wno-cast-function-type-strict -Wno-reserved-identifier \
-	   -Wno-reserved-macro-identifier -Wno-unsafe-buffer-usage
+	   -Wno-reserved-macro-identifier -Wno-unsafe-buffer-usage \
+	   -Wno-unknown-warning-option
 #
 CWARN+= -Weverything
 #

2013/endoh1/Makefile

@@ -39,7 +39,7 @@ include ../../var.mk
 # Common C compiler warnings to silence
 #
 CSILENCE= -Wno-deprecated-non-prototype -Wno-strict-prototypes \
-	  -Wno-maybe-uninitialized
+	  -Wno-maybe-uninitialized -Wno-unknown-warning-option
 
 # Common C compiler warning flags
 #

2013/endoh3/Makefile

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

2013/robison/Makefile

@@ -39,7 +39,8 @@ include ../../var.mk
 # Common C compiler warnings to silence
 #
 CSILENCE= -Wno-parentheses -Wno-unused-variable \
-	  -Wno-misleading-indentation -Wno-stringop-truncation
+	  -Wno-misleading-indentation -Wno-stringop-truncation \
+	  -Wno-unknown-warning-option
 
 # Common C compiler warning flags
 #