overhaul implementation-internal signal protections

the new approach relies on the fact that the only ways to create
sigset_t objects without invoking UB are to use the sig*set()
functions, or from the masks returned by sigprocmask, sigaction, etc.
or in the ucontext_t argument to a signal handler. thus, as long as
sigfillset and sigaddset avoid adding the "protected" signals, there
is no way the application will ever obtain a sigset_t including these
bits, and thus no need to add the overhead of checking/clearing them
when sigprocmask or sigaction is called.

note that the old code actually *failed* to remove the bits from
sa_mask when sigaction was called.

the new implementations are also significantly smaller, simpler, and
faster due to ignoring the useless "GNU HURD signals" 65-1024, which
are not used and, if there's any sanity in the world, never will be
used.

1 files changed, 1 insertions, 1 deletions

diff --git a/dist/config.mak b/dist/config.mak
index 691e3ce1..66aa44cd 100644
--- a/dist/config.mak
+++ b/dist/config.mak
@@ -18,7 +18,7 @@ exec_prefix = /usr/local
 #CFLAGS += -fomit-frame-pointer -mno-accumulate-outgoing-args
 
 # Uncomment for warnings (as errors). Might need tuning to your gcc version.
-#CFLAGS += -Werror -Wall -Wpointer-arith -Wcast-align -Wno-parentheses -Wno-char-subscripts -Wno-uninitialized -Wno-sequence-point -Wno-missing-braces -Wno-unused-value
+#CFLAGS += -Werror -Wall -Wpointer-arith -Wcast-align -Wno-parentheses -Wno-char-subscripts -Wno-uninitialized -Wno-sequence-point -Wno-missing-braces -Wno-unused-value -Wno-overflow -Wno-int-to-pointer-cast
 
 # Uncomment if you want to build a shared library (experimental).
 #LIBC_LIBS += lib/libc.so