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
```

1988/applin/Makefile

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

1988/dale/Makefile

@@ -39,7 +39,8 @@ include ../../var.mk
 # Common C compiler warnings to silence
 #
 CSILENCE= -Wno-implicit-function-declaration -Wno-implicit-int -Wno-keyword-macro \
-	-Wno-pointer-to-int-cast -Wno-return-type -Wno-unused-value
+	-Wno-pointer-to-int-cast -Wno-return-type -Wno-unused-value \
+	-Wno-deprecated-non-prototype
 
 # Common C compiler warning flags
 #
@@ -84,7 +85,9 @@ CC= cc
 #
 ifeq ($(CC),clang)
 #
-CSILENCE+= -Wno-poison-system-directories
+CSILENCE+= -Wno-poison-system-directories -Wno-comma -Wno-missing-prototypes \
+	-Wno-missing-variable-declarations -Wno-pedantic -Wno-shorten-64-to-32 \
+	-Wno-unused-macros
 #
 CWARN+= -Weverything
 #

1988/isaak/Makefile

@@ -42,7 +42,7 @@ CSILENCE=  -Wno-comma -Wno-implicit-function-declaration -Wno-format-insufficien
 	-Wno-implicit-int -Wno-incompatible-library-redeclaration -Wno-missing-prototypes \
 	-Wno-missing-variable-declarations -Wno-poison-system-directories -Wno-return-type \
 	-Wno-shadow -Wno-shift-op-parentheses -Wno-strict-prototypes -Wno-unreachable-code \
-	-Wno-unused-macros
+	-Wno-unused-macros -Wno-int-conversion -Wno-macro-redefined
 
 # Common C compiler warning flags
 #

1988/litmaath/Makefile

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

1988/phillipps/Makefile

@@ -40,7 +40,8 @@ include ../../var.mk
 #
 CSILENCE= -Wno-pedantic -Wno-logical-not-parentheses -Wno-implicit-function-declaration \
 	-Wno-incompatible-pointer-types -Wno-int-conversion -Wno-pointer-to-int-cast \
-	-Wno-pointer-integer-compare -Wno-compare-distinct-pointer-types
+	-Wno-pointer-integer-compare -Wno-compare-distinct-pointer-types \
+	-Wno-deprecated-non-prototype
 
 # Common C compiler warning flags
 #
@@ -85,7 +86,8 @@ CC= cc
 #
 ifeq ($(CC),clang)
 #
-CSILENCE+= -Wno-poison-system-directories -Wno-comma
+CSILENCE+= -Wno-poison-system-directories -Wno-comma \
+	-Wno-missing-prototypes
 #
 CWARN+= -Weverything
 #

1988/reddy/Makefile

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

1988/robison/Makefile

@@ -38,7 +38,7 @@ include ../../var.mk
 
 # Common C compiler warnings to silence
 #
-CSILENCE= -Wno-error -Wno-implicit-function-declaration
+CSILENCE= -Wno-error -Wno-implicit-function-declaration -Wno-deprecated-non-prototype
 
 # Common C compiler warning flags
 #

1988/westley/Makefile

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