gcc10: add plugin

static qt5 okay, shared fails at glib

plugins/gcc10/gcc10-overlay.mk

@@ -0,0 +1,35 @@
+# This file is part of MXE. See LICENSE.md for licensing information.
+
+# override relevant cloog, isl, and gcc variables changed in:
+# https://github.com/mxe/mxe/pull/965
+#
+# simply expanded variables (*_SUBDIR, *_FILE, etc.) need to be set
+
+PKG             := cloog
+$(PKG)_TARGETS  := $(MXE_TARGETS)
+
+PKG             := isl
+$(PKG)_VERSION  := 0.16.1
+$(PKG)_CHECKSUM := 412538bb65c799ac98e17e8cfcdacbb257a57362acfaaff254b0fcae970126d2
+$(PKG)_SUBDIR   := $(PKG)-$($(PKG)_VERSION)
+$(PKG)_FILE     := $(PKG)-$($(PKG)_VERSION).tar.bz2
+$(PKG)_URL      := https://isl.gforge.inria.fr/$($(PKG)_FILE)
+$(PKG)_URL_2    := https://gcc.gnu.org/pub/gcc/infrastructure/$($(PKG)_FILE)
+
+PKG             := gcc
+$(PKG)_VERSION  := 10.1.0
+$(PKG)_CHECKSUM := b6898a23844b656f1b68691c5c012036c2e694ac4b53a8918d4712ad876e7ea2
+$(PKG)_SUBDIR   := gcc-$($(PKG)_VERSION)
+$(PKG)_FILE     := gcc-$($(PKG)_VERSION).tar.xz
+$(PKG)_URL      := https://ftp.gnu.org/gnu/gcc/gcc-$($(PKG)_VERSION)/$($(PKG)_FILE)
+$(PKG)_URL_2    := https://www.mirrorservice.org/sites/sourceware.org/pub/gcc/releases/gcc-$($(PKG)_VERSION)/$($(PKG)_FILE)
+$(PKG)_PATCHES  := $(dir $(lastword $(MAKEFILE_LIST)))/gcc10.patch
+
+# copy db-2-install-exe.patch to gcc7 plugin when gcc10 is default
+db_PATCHES := $(TOP_DIR)/src/db-1-fix-including-winioctl-h-lowcase.patch
+
+# set these in respective makefiles when gcc10 becomes default
+# remove from here and leave them blank for gcc5 plugin
+libssh_EXTRA_WARNINGS = -Wno-error=implicit-fallthrough
+gtkimageview_EXTRA_WARNINGS = -Wno-error=misleading-indentation
+guile_EXTRA_WARNINGS = -Wno-error=misleading-indentation

plugins/gcc10/gcc10.patch

@@ -0,0 +1,69 @@
+This file is part of MXE. See LICENSE.md for licensing information.
+
+Contains ad hoc patches for cross building.
+
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Tony Theodore <tonyt@logyst.com>
+Date: Sun, 10 May 2020 15:06:47 +1000
+Subject: [PATCH 1/2] allow native cpu detection when building with clang
+
+function was disabled for non-gcc5 in:
+https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=b587c12551143c14f023860a1dbdf7316ae71f27;hp=43096b526a9f23008b9769372f11475ae63487bc
+
+clang can build it correctly and this should probably be a feature test
+
+diff --git a/gcc/config/i386/driver-i386.c b/gcc/config/i386/driver-i386.c
+index 1111111..2222222 100644
+--- a/gcc/config/i386/driver-i386.c
++++ b/gcc/config/i386/driver-i386.c
+@@ -26,7 +26,7 @@ along with GCC; see the file COPYING3.  If not see
+ 
+ const char *host_detect_local_cpu (int argc, const char **argv);
+ 
+-#if defined(__GNUC__) && (__GNUC__ >= 5 || !defined(__PIC__))
++#if defined(__GNUC__) && (__GNUC__ >= 5 || !defined(__PIC__)) || defined(__clang__)
+ #include "cpuid.h"
+ 
+ struct cache_desc
+
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Tony Theodore <tonyt@logyst.com>
+Date: Sun, 10 May 2020 15:09:58 +1000
+Subject: [PATCH 2/2] remove hard-coded mingw from paths
+
+
+diff --git a/gcc/config.gcc b/gcc/config.gcc
+index 1111111..2222222 100644
+--- a/gcc/config.gcc
++++ b/gcc/config.gcc
+@@ -2169,7 +2169,7 @@ i[34567]86-*-mingw* | x86_64-*-mingw*)
+ 			tmake_file="${tmake_file} i386/t-mingw-w32"
+ 			;;
+ 	esac
+-        native_system_header_dir=/mingw/include
++        native_system_header_dir=/include
+ 	target_gtfiles="$target_gtfiles \$(srcdir)/config/i386/winnt.c"
+ 	extra_options="${extra_options} i386/cygming.opt i386/mingw.opt"
+ 	case ${target} in
+diff --git a/gcc/config/i386/mingw32.h b/gcc/config/i386/mingw32.h
+index 1111111..2222222 100644
+--- a/gcc/config/i386/mingw32.h
++++ b/gcc/config/i386/mingw32.h
+@@ -186,7 +186,7 @@ along with GCC; see the file COPYING3.  If not see
+ 
+ /* Override startfile prefix defaults.  */
+ #ifndef STANDARD_STARTFILE_PREFIX_1
+-#define STANDARD_STARTFILE_PREFIX_1 "/mingw/lib/"
++#define STANDARD_STARTFILE_PREFIX_1 "/lib/"
+ #endif
+ #ifndef STANDARD_STARTFILE_PREFIX_2
+ #define STANDARD_STARTFILE_PREFIX_2 ""
+@@ -195,7 +195,7 @@ along with GCC; see the file COPYING3.  If not see
+ /* For native mingw-version we need to take care that NATIVE_SYSTEM_HEADER_DIR
+    macro contains POSIX-style path.  See bug 52947.  */
+ #undef NATIVE_SYSTEM_HEADER_DIR
+-#define NATIVE_SYSTEM_HEADER_DIR "/mingw/include"
++#define NATIVE_SYSTEM_HEADER_DIR "/include"
+ 
+ /* Output STRING, a string representing a filename, to FILE.
+    We canonicalize it to be in Unix format (backslashes are replaced