Toolchain+Ports: Split the GCC patches

This shouldn't cause any breaking changes, so a toolchain rebuild is not
required.

As per Hendiadyoin's request, math errno is disabled by default, which
should enable some extra compiler optimizations in LibGL and LibSoftGPU
code that uses math functions heavily.

Co-Authored-By: Ali Mohammad Pur <mpfard@serenityos.org>

Toolchain/Patches/gcc/0006-libstdc-Support-SerenityOS.patch

@@ -0,0 +1,120 @@
+From b581fd421af5691bdafda7d30b20723f77d0cc88 Mon Sep 17 00:00:00 2001
+From: Andreas Kling <awesomekling@gmail.com>
+Date: Mon, 16 May 2022 15:08:53 +0200
+Subject: [PATCH 6/6] libstdc++: Support SerenityOS
+
+During the toolchain build, SerenityOS libraries are not available, so
+we have to manually tell libstdc++ about what our LibC supports.
+
+In most places, we take the Newlib code paths.
+
+Co-Authored-By: Gunnar Beutner <gbeutner@serenityos.org>
+Co-Authored-By: Daniel Bertalan <dani@danielbertalan.dev>
+Co-Authored-By: Itamar <itamar8910@gmail.com>
+Co-Authored-By: James Mintram <me@jamesrm.com>
+Co-Authored-By: Martin Bříza <m@rtinbriza.cz>
+Co-Authored-By: Nico Weber <thakis@chromium.org>
+Co-Authored-By: Philip Herron <herron.philip@googlemail.com>
+Co-Authored-By: Shannon Booth <shannon.ml.booth@gmail.com>
+---
+ libstdc++-v3/acinclude.m4   |  4 ++--
+ libstdc++-v3/configure      | 11 ++++++++---
+ libstdc++-v3/configure.host |  3 +++
+ libstdc++-v3/crossconfig.m4 |  2 +-
+ 4 files changed, 14 insertions(+), 6 deletions(-)
+
+diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
+index 138bd58d8..6cd7564b6 100644
+--- a/libstdc++-v3/acinclude.m4
++++ b/libstdc++-v3/acinclude.m4
+@@ -1374,7 +1374,7 @@ AC_DEFUN([GLIBCXX_ENABLE_LIBSTDCXX_TIME], [
+         ac_has_nanosleep=yes
+         ac_has_sched_yield=yes
+         ;;
+-      freebsd*|netbsd*|dragonfly*|rtems*)
++      freebsd*|netbsd*|dragonfly*|rtems*|serenity*)
+         ac_has_clock_monotonic=yes
+         ac_has_clock_realtime=yes
+         ac_has_nanosleep=yes
+@@ -2421,7 +2421,7 @@ AC_DEFUN([GLIBCXX_ENABLE_CLOCALE], [
+       dragonfly* | freebsd*)
+ 	enable_clocale_flag=dragonfly
+ 	;;
+-      openbsd*)
++      openbsd* | serenity*)
+ 	enable_clocale_flag=newlib
+ 	;;
+       *)
+diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure
+index 9b94fd71e..51e45878f 100755
+--- a/libstdc++-v3/configure
++++ b/libstdc++-v3/configure
+@@ -11914,6 +11914,11 @@ else
+     lt_cv_dlopen_libs=
+     ;;
+ 
++  serenity*)
++    lt_cv_dlopen="dlopen"
++    lt_cv_dlopen_libs="-ldl"
++    ;;
++
+   darwin*)
+   # if libdl is installed we need to link against it
+     { $as_echo "$as_me:${as_lineno-$LINENO}: checking for dlopen in -ldl" >&5
+@@ -16478,7 +16483,7 @@ fi
+       dragonfly* | freebsd*)
+ 	enable_clocale_flag=dragonfly
+ 	;;
+-      openbsd*)
++      openbsd* | serenity*)
+ 	enable_clocale_flag=newlib
+ 	;;
+       *)
+@@ -20569,7 +20574,7 @@ fi
+         ac_has_nanosleep=yes
+         ac_has_sched_yield=yes
+         ;;
+-      freebsd*|netbsd*|dragonfly*|rtems*)
++      freebsd*|netbsd*|dragonfly*|rtems*|serenity*)
+         ac_has_clock_monotonic=yes
+         ac_has_clock_realtime=yes
+         ac_has_nanosleep=yes
+@@ -29245,7 +29250,7 @@ case "${host}" in
+     # This is a freestanding configuration; there is nothing to do here.
+     ;;
+ 
+-  avr*-*-*)
++  avr*-*-* | *serenity*)
+     $as_echo "#define HAVE_ACOSF 1" >>confdefs.h
+ 
+     $as_echo "#define HAVE_ASINF 1" >>confdefs.h
+diff --git a/libstdc++-v3/configure.host b/libstdc++-v3/configure.host
+index ec32980aa..e060300f3 100644
+--- a/libstdc++-v3/configure.host
++++ b/libstdc++-v3/configure.host
+@@ -297,6 +297,9 @@ case "${host_os}" in
+     # Use libatomic if necessary and avoid libstdc++ specific atomicity support
+     atomicity_dir="cpu/generic/atomicity_builtins"
+     ;;
++  serenity*)
++    os_include_dir="os/newlib"
++    ;;
+   solaris2*)
+     os_include_dir="os/solaris"
+     ;;
+diff --git a/libstdc++-v3/crossconfig.m4 b/libstdc++-v3/crossconfig.m4
+index ae5283b7a..b9fc96e94 100644
+--- a/libstdc++-v3/crossconfig.m4
++++ b/libstdc++-v3/crossconfig.m4
+@@ -9,7 +9,7 @@ case "${host}" in
+     # This is a freestanding configuration; there is nothing to do here.
+     ;;
+ 
+-  avr*-*-*)
++  avr*-*-* | *serenity*)
+     AC_DEFINE(HAVE_ACOSF)
+     AC_DEFINE(HAVE_ASINF)
+     AC_DEFINE(HAVE_ATAN2F)
+-- 
+2.36.1
+