toolchain: gccgo: fix building gccgo compiler

Fixes FS#1498.  "gccgo -static" can fail for missing linker flag
-lgcc_eh caused by patch 850-use_shared_libgcc.patch

Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>

1 files changed, 73 insertions, 0 deletions

diff --git a/toolchain/gcc/patches/7.3.0/960-gotools-fix-compilation-when-making-cross-compiler.patch b/toolchain/gcc/patches/7.3.0/960-gotools-fix-compilation-when-making-cross-compiler.patch
new file mode 100644
index 0000000000..556fa16473
--- /dev/null
+++ b/toolchain/gcc/patches/7.3.0/960-gotools-fix-compilation-when-making-cross-compiler.patch
@@ -0,0 +1,73 @@
+From dda6b050cd74a352670787a294596a9c56c21327 Mon Sep 17 00:00:00 2001
+From: Yousong Zhou <yszhou4tech@gmail.com>
+Date: Fri, 4 May 2018 18:20:53 +0800
+Subject: [PATCH] gotools: fix compilation when making cross compiler
+
+libgo is "the runtime support library for the Go programming language.
+This library is intended for use with the Go frontend."
+
+gccgo will link target files with libgo.so which depends on libgcc_s.so.1, but
+the linker will complain that it cannot find it.  That's because shared libgcc
+is not present in the install directory yet.  libgo.so was made without problem
+because gcc will emit -lgcc_s when compiled with -shared option.  When gotools
+were being made, it was supplied with -static-libgcc thus no link option was
+provided.  Check LIBGO in gcc/go/gcc-spec.c for how gccgo make a builtin spec
+for linking with libgo.so
+
+- GccgoCrossCompilation, https://github.com/golang/go/wiki/GccgoCrossCompilation
+- Cross-building instructions, http://www.eglibc.org/archives/patches/msg00078.html
+
+When 3-pass GCC compilation is used, shared libgcc runtime libraries will be
+available after gcc pass2 completed and will meet the gotools link requirement
+at gcc pass3
+---
+ gotools/Makefile.am | 4 +++-
+ gotools/Makefile.in | 4 +++-
+ 2 files changed, 6 insertions(+), 2 deletions(-)
+
+diff --git a/gotools/Makefile.am b/gotools/Makefile.am
+index 5f3940a278b..9c22f5df103 100644
+--- a/gotools/Makefile.am
++++ b/gotools/Makefile.am
+@@ -26,6 +26,7 @@ PWD_COMMAND = $${PWDCMD-pwd}
+ STAMP = echo timestamp >
+ 
+ libgodir = ../$(target_noncanonical)/libgo
++libgccdir = ../$(target_noncanonical)/libgcc
+ LIBGODEP = $(libgodir)/libgo.la
+ 
+ if NATIVE
+@@ -38,7 +39,8 @@ endif
+ GOCFLAGS = $(CFLAGS_FOR_TARGET)
+ GOCOMPILE = $(GOCOMPILER) $(GOCFLAGS)
+ 
+-AM_LDFLAGS = -L $(libgodir) -L $(libgodir)/.libs
++AM_LDFLAGS = -L $(libgodir) -L $(libgodir)/.libs \
++	-L $(libgccdir) -L $(libgccdir)/.libs -lgcc_s
+ GOLINK = $(GOCOMPILER) $(GOCFLAGS) $(AM_GOCFLAGS) $(LDFLAGS) $(AM_LDFLAGS) -o $@
+ 
+ cmdsrcdir = $(srcdir)/../libgo/go/cmd
+diff --git a/gotools/Makefile.in b/gotools/Makefile.in
+index 4386576b011..0bdd9290e01 100644
+--- a/gotools/Makefile.in
++++ b/gotools/Makefile.in
+@@ -252,13 +252,15 @@ mkinstalldirs = $(SHELL) $(toplevel_srcdir)/mkinstalldirs
+ PWD_COMMAND = $${PWDCMD-pwd}
+ STAMP = echo timestamp >
+ libgodir = ../$(target_noncanonical)/libgo
++libgccdir = ../$(target_noncanonical)/libgcc
+ LIBGODEP = $(libgodir)/libgo.la
+ @NATIVE_FALSE@GOCOMPILER = $(GOC)
+ 
+ # Use the compiler we just built.
+ @NATIVE_TRUE@GOCOMPILER = $(GOC_FOR_TARGET) $(XGCC_FLAGS_FOR_TARGET)
+ GOCOMPILE = $(GOCOMPILER) $(GOCFLAGS)
+-AM_LDFLAGS = -L $(libgodir) -L $(libgodir)/.libs
++AM_LDFLAGS = -L $(libgodir) -L $(libgodir)/.libs \
++	-L $(libgccdir) -L $(libgccdir)/.libs -lgcc_s
+ GOLINK = $(GOCOMPILER) $(GOCFLAGS) $(AM_GOCFLAGS) $(LDFLAGS) $(AM_LDFLAGS) -o $@
+ cmdsrcdir = $(srcdir)/../libgo/go/cmd
+ go_cmd_go_files = \
+-- 
+2.16.3
+