Restore silencing warnings in macOS

As besides the entries that are not supposed to compile/cannot compile
due to architectural limitations all the entries can compile in macOS
(though some do not work - yet(? I have plans to work on more later)) it
was not necessary to not silence the warnings after all as the entries
that don't work will be easy to identify ('they don't work' :-) ) so I
can just do make CSILENCE= all in the directory of those entries which
solves the problem I had originally thought of.

Some of the Makefiles have retained other changes I had to make
yesterday to get the entries to work with clang in linux but most of
them were either not changed or were made better with the rollback of
the commit that originally silenced warnings.

Now work on silencing warnings for linux can be done.

1990/dds/Makefile

@@ -40,7 +40,8 @@ include ../../var.mk
 #
 CSILENCE= -Wno-builtin-requires-header -Wno-char-subscripts -Wno-conditional-type-mismatch \
 	-Wno-empty-body -Wno-error -Wno-implicit-function-declaration \
-	-Wno-incompatible-library-redeclaration -Wno-parentheses -Wno-implicit-int
+	-Wno-incompatible-library-redeclaration -Wno-parentheses -Wno-implicit-int \
+	-Wno-deprecated-non-prototype -Wno-return-type -Wno-strict-prototypes
 
 # Common C compiler warning flags
 #
@@ -85,7 +86,9 @@ CC= cc
 #
 ifeq ($(CC),clang)
 #
-#CSILENCE+=
+CSILENCE+= -Wno-comma -Wno-missing-prototypes -Wno-missing-variable-declarations \
+	-Wno-poison-system-directories -Wno-shadow -Wno-shorten-64-to-32 \
+	-Wno-unreachable-code-return
 #
 CWARN+= -Weverything
 #