properly fix our libstdc++ build.

remove our local _GLIBCXX_COMPAT_ bits, and properly build like upstream
does, for the static vs shared libraries.

now we both aren't missing std::istream::ignore(long) or the old compat
std::condition_variable::wait(std::unique_lock<std::mutex>&) that some
of the rust binary bootstraps need.  this makes rust build again on arm64,
and (probably) fixes the same for sparc64 (that build won't finish for
a bit more...)

Author: mrgtwentythree

external/gpl3/gcc/dist/libstdc++-v3/src/c++11/compatibility-atomic-c++0x.cc

@@ -150,12 +150,8 @@ _GLIBCXX_END_NAMESPACE_VERSION
     && defined(_GLIBCXX_HAVE_AS_SYMVER_DIRECTIVE) \
     && defined(_GLIBCXX_HAVE_SYMVER_SYMBOL_RENAMING_RUNTIME_SUPPORT)
 
-#ifdef _GLIBCXX_COMPAT_
 #define _GLIBCXX_ASM_SYMVER(cur, old, version) \
    asm (".symver " #cur "," #old "@@" #version);
-#else
-#define _GLIBCXX_ASM_SYMVER(cur, old, version)
-#endif
 
 _GLIBCXX_ASM_SYMVER(_ZNSt9__atomic011atomic_flag5clearESt12memory_order, _ZNVSt9__atomic011atomic_flag5clearESt12memory_order, GLIBCXX_3.4.11)
 

external/gpl3/gcc/dist/libstdc++-v3/src/c++11/compatibility-thread-c++0x.cc

@@ -39,12 +39,8 @@
 # error "compatibility-thread-c++0x.cc is not needed for gnu-versioned-namespace"
 #endif
 
-#ifdef _GLIBCXX_COMPAT_
 #define _GLIBCXX_ASM_SYMVER(cur, old, version) \
    asm (".symver " #cur "," #old "@@@" #version);
-#else
-#define _GLIBCXX_ASM_SYMVER(cur, old, version)
-#endif
 
 // XXX GLIBCXX_ABI Deprecated
 // gcc-4.6.0

external/gpl3/gcc/dist/libstdc++-v3/src/c++98/compatibility.cc

@@ -381,7 +381,6 @@ _GLIBCXX_END_NAMESPACE_VERSION
 // In the future, GLIBCXX_ABI > 6 should remove all uses of
 // _GLIBCXX_*_SYMVER macros in this file.
 
-#ifdef _GLIBCXX_COMPAT_
 #define _GLIBCXX_3_4_SYMVER(XXname, name) \
    extern "C" void \
    _X##name(...) \
@@ -396,11 +395,6 @@ _GLIBCXX_END_NAMESPACE_VERSION
 
 #define _GLIBCXX_ASM_SYMVER(cur, old, version) \
    asm (".symver " #cur "," #old "@@" #version);
-#else
-#define _GLIBCXX_3_4_SYMVER(XXname, name)
-#define _GLIBCXX_3_4_5_SYMVER(XXname, name)
-#define _GLIBCXX_ASM_SYMVER(cur, old, version)
-#endif
 
 #define _GLIBCXX_APPLY_SYMVER _GLIBCXX_3_4_SYMVER
 #include <abi/compatibility.h>

external/gpl3/gcc/dist/libstdc++-v3/src/c++98/istream.cc

@@ -112,7 +112,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     basic_istream<char>::
     ignore(streamsize __n, int_type __delim)
     {
-#ifdef _GLIBCXX_COMPAT_
       {
 	// If conversion to int_type changes the value then __delim does not
 	// correspond to a value of type char_type, and so will never match
@@ -124,7 +123,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	// Now we know that __delim is a valid char_type value, so it's safe
 	// for the code below to use traits_type::find to search for it.
       }
-#endif
 
       _M_gcount = 0;
       sentry __cerb(*this, true);
@@ -376,10 +374,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     basic_istream<wchar_t>::
     ignore(streamsize __n, int_type __delim)
     {
-#ifdef _GLIBCXX_COMPAT_
       if (traits_type::eq_int_type(__delim, traits_type::eof()))
 	return ignore(__n);
-#endif
 
       _M_gcount = 0;
       sentry __cerb(*this, true);

external/gpl3/gcc/lib/libstdc++-v3/Makefile

@@ -1,4 +1,4 @@
-#	$NetBSD: Makefile,v 1.61 2025/10/14 09:17:05 mrg Exp $
+#	$NetBSD: Makefile,v 1.62 2025/10/15 06:04:43 mrg Exp $
 
 REQUIRETOOLS=	yes
 NOLINT=		# defined
@@ -62,10 +62,9 @@ SRCS=		${LIBSUPCXXSRCS} ${LIBSTDCXXSRCS}
 
 GCC_MACHINE_SUBDIR=${MACHINE_CPU:C/powerpc.*/rs6000/:C/x86_64/i386/}
 
-# The compatibility files are built without -D_GLIBCXX_SHARED.
-.for s in ${SRCS:Ncompatibility.cc:Ncompatibility-debug_list.cc:Ncompatibility-debug_list-2.cc:Ncompatibility-atomic-c++0x.cc:Ncompatibility-c++0x.cc:Ncompatibility-chrono.cc:Ncompatibility-condvar.cc:Ncompatibility-thread-c++0x.cc}
-CSHLIBFLAGS.${s}+=	-D_GLIBCXX_SHARED
-.endfor
+# Only the shared library is build with -D_GLIBCXX_SHARED, and the
+# static library shouldn't need to provide old symbols.
+CSHLIBFLAGS+=	-D_GLIBCXX_SHARED
 
 CXXFLAGS+=	-fno-implicit-templates
 CPPFLAGS+=	-I${DIST}/libstdc++-v3/include