silence warnings under macOS for cc, clang and gcc

Used the following script to check for warnings
not silenced via ${CSILENCE}:

```sh
find ???? -mindepth 1 -maxdepth 1 -type d | while read dir; do
(cd "$dir"; echo =-=-= "$dir" =-=-= ; csilence -v 1 clobber all ; echo ; csilence -v 1 clobber alt)
done 2>&1 | less
```

1991/ant/Makefile

@@ -39,7 +39,8 @@ include ../../var.mk
 # Common C compiler warnings to silence
 #
 CSILENCE= -Wno-error -Wno-implicit-function-declaration -Wno-empty-body \
-	-Wno-implicit-function-declaration -Wno-return-type
+	-Wno-implicit-function-declaration -Wno-return-type \
+	-Wno-deprecated-non-prototype
 
 # Common C compiler warning flags
 #

1991/brnstnd/Makefile

@@ -39,7 +39,7 @@ include ../../var.mk
 # Common C compiler warnings to silence
 #
 CSILENCE= -Wno-c99-extensions -Wno-error -Wno-implicit-function-declaration \
-	-Wno-parentheses -Wno-return-type
+	-Wno-parentheses -Wno-return-type -Wno-deprecated-non-prototype -Wno-unused-value
 
 # Common C compiler warning flags
 #
@@ -86,7 +86,8 @@ ifeq ($(CC),clang)
 #
 CSILENCE+= -Wno-implicit-int-conversion -Wno-missing-prototypes \
 	-Wno-missing-variable-declarations -Wno-poison-system-directories \
-	-Wno-shorten-64-to-32 -Wno-sign-conversion -Wno-strict-prototypes
+	-Wno-shorten-64-to-32 -Wno-sign-conversion -Wno-strict-prototypes \
+	-Wno-unused-macros
 #
 CWARN+= -Weverything
 #

1991/buzzard/Makefile

@@ -40,7 +40,8 @@ include ../../var.mk
 #
 CSILENCE= -Wno-char-subscripts -Wno-error -Wno-implicit-function-declaration \
 	-Wno-int-conversion -Wno-logical-op-parentheses -Wno-pedantic \
-	-Wno-return-type -Wno-unknown-escape-sequence -Wno-unused-value
+	-Wno-return-type -Wno-unknown-escape-sequence -Wno-unused-value \
+	-Wno-deprecated-non-prototype
 
 # Common C compiler warning flags
 #

1991/cdupont/Makefile

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

1991/davidguy/Makefile

@@ -39,7 +39,8 @@ include ../../var.mk
 # Common C compiler warnings to silence
 #
 CSILENCE= -Wno-bitwise-op-parentheses -Wno-error -Wno-implicit-function-declaration \
-	-Wno-int-to-pointer-cast -Wno-return-type -Wno-sign-compare
+	-Wno-int-to-pointer-cast -Wno-return-type -Wno-sign-compare \
+	-Wno-deprecated-non-prototype
 
 # Common C compiler warning flags
 #

1991/dds/Makefile

@@ -38,8 +38,8 @@ include ../../var.mk
 
 # Common C compiler warnings to silence
 #
-CSILENCE= -Wno-error -Wno-implicit-function-declaration -Wno-overlength-strings \
-	-Wno-unused-parameter
+CSILENCE= -Wno-deprecated-non-prototype -Wno-unused-parameter \
+	-Wno-error -Wno-implicit-function-declaration
 
 # Common C compiler warning flags
 #
@@ -80,13 +80,13 @@ LIBS=
 #
 CC= cc
 
-CSILENCE= -Wno-implicit-function-declaration
 # Compiler add-ons or replacements for clang only
 #
 ifeq ($(CC),clang)
 #
-CSILENCE+= -Wno-implicit-int-conversion -Wno-missing-variable-declarations \
-	-Wno-pedantic -Wno-poison-system-directorie
+CSILENCE+= -Wno-deprecated-non-prototype -Wno-implicit-int-conversion \
+	-Wno-missing-variable-declarations -Wno-overlength-strings -Wno-pedantic \
+	-Wno-poison-system-directories -Wno-unused-parameter
 #
 CWARN+= -Weverything
 #

1991/rince/Makefile

@@ -38,7 +38,8 @@ include ../../var.mk
 
 # Common C compiler warnings to silence
 #
-CSILENCE= -Wno-error -Wno-implicit-function-declaration -Wno-parentheses
+CSILENCE= -Wno-error -Wno-implicit-function-declaration -Wno-parentheses \
+	-Wno-strict-prototypes
 
 # Common C compiler warning flags
 #

1991/westley/Makefile

@@ -39,7 +39,8 @@ include ../../var.mk
 # Common C compiler warnings to silence
 #
 CSILENCE= -Wno-error -Wno-implicit-function-declaration -Wno-parentheses \
-	-Wno-shift-op-parentheses -Wno-return-type
+	-Wno-shift-op-parentheses -Wno-return-type -Wno-deprecated-non-prototype \
+	-Wno-missing-braces
 
 # Common C compiler warning flags
 #