[newlib-cygwin] cxx.cc: Fix dynamic initialization for static local variables

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=9e88e840c2062ee1492e303da5fc696eec849328

commit 9e88e840c2062ee1492e303da5fc696eec849328
Author: Ben Wijen <ben@wijen.net>
Date:   Fri Jan 15 14:45:29 2021 +0100

    cxx.cc: Fix dynamic initialization for static local variables
    
    The old implementation for __cxa_guard_acquire did not return 1,
    therefore dynamic initialization was never performed.
    
    If concurrent-safe dynamic initialisation is ever needed, CXX ABI
    must be followed when re-implementing __cxa_guard_acquire (et al.)

Diff:
---
 winsup/cygwin/Makefile.in |  2 +-
 winsup/cygwin/cxx.cc      | 10 ----------
 2 files changed, 1 insertion(+), 11 deletions(-)

diff --git a/winsup/cygwin/Makefile.in b/winsup/cygwin/Makefile.in
index a840f2b83..73d9b37fd 100644
--- a/winsup/cygwin/Makefile.in
+++ b/winsup/cygwin/Makefile.in
@@ -69,7 +69,7 @@ COMMON_CFLAGS=-MMD ${$(*F)_CFLAGS} -Wimplicit-fallthrough=5 -Werror -fmerge-cons
 ifeq ($(target_cpu),x86_64)
 COMMON_CFLAGS+=-mcmodel=small
 endif
-COMPILE.cc+=${COMMON_CFLAGS} # -std=gnu++14
+COMPILE.cc+=${COMMON_CFLAGS} -fno-threadsafe-statics # -std=gnu++14
 COMPILE.c+=${COMMON_CFLAGS}
 
 AR:=@AR@
diff --git a/winsup/cygwin/cxx.cc b/winsup/cygwin/cxx.cc
index be3268549..b69524aca 100644
--- a/winsup/cygwin/cxx.cc
+++ b/winsup/cygwin/cxx.cc
@@ -83,16 +83,6 @@ __cxa_pure_virtual (void)
   api_fatal ("pure virtual method called");
 }
 
-extern "C" void
-__cxa_guard_acquire ()
-{
-}
-
-extern "C" void
-__cxa_guard_release ()
-{
-}
-
 /* These routines are made available as last-resort fallbacks
    for the application.  Should not be used in practice; the
    entries in this struct get overwritten by each DLL as it