- Add gccgo symlink, add go and gofmt as alternatives to support

parallel install of golang.  [bnc#1096677]

OBS-URL: https://build.opensuse.org/package/show/devel:gcc/gcc?expand=0&rev=88

gcc.spec

@@ -345,6 +345,8 @@ License:        GPL-3.0+
 Group:          Development/Languages/C and C++
 Requires:       gcc = %{version}
 Requires:       gcc%{gcc_version}-go
+Requires(post): update-alternatives
+Requires(postun): update-alternatives
 
 %description -n gcc-go
 The system GNU Go Compiler.
@@ -385,6 +387,7 @@ for program in \
         g++ \
         cpp \
         gfortran \
+	gccgo \
 %if %{build_ada}
 	gnat gnatbind gnatbl gnatchop gnatclean gnatfind gnatkr \
 	gnatlink gnatls gnatmake gnatname gnatprep gnatxref gprmake \
@@ -393,12 +396,17 @@ for program in \
     ; do
   ln -sf $program-%{gcc_suffix} $RPM_BUILD_ROOT%{_prefix}/bin/$program
 done
+# For go and gofmt use alternatives since they are shared with golang
+mkdir -p %{buildroot}%{_sysconfdir}/alternatives
+ln -sf %{_sysconfdir}/alternatives/go %{buildroot}%{_bindir}/go
+ln -sf %{_sysconfdir}/alternatives/gofmt %{buildroot}%{_bindir}/gofmt
 # Link section 1 manpages
 for man1 in \
         gcc gcov gcov-dump gcov-tool \
         g++ \
         cpp \
         gfortran \
+	gccgo \
     ; do
   ln -sf $man1-%{gcc_suffix}.1.gz $RPM_BUILD_ROOT%{_mandir}/man1/$man1.1.gz
 done
@@ -426,6 +434,20 @@ cat > $RPM_BUILD_ROOT/$dir/defaults.spec <<EOF
 %%{pie|fpic|fPIC|fpie|fPIE|no-pie|fno-pic|fno-PIC|fno-pie|fno-PIE|shared|static|nostdlib|nodefaultlibs|nostartfiles:;:-fPIE -pie}
 EOF
 
+%post -n gcc-go
+# we don't want a BuildRequires on gccN-go but otherwise the install
+# step of the build fails, so simply skip the script when gccN-go isn't there
+if [ -f %{_bindir}/go-%{gcc_suffix} ] ; then
+update-alternatives \
+  --install %{_bindir}/go go %{_bindir}/go-%{gcc_suffix} 100 \
+  --slave %{_bindir}/gofmt gofmt %{_bindir}/gofmt-%{gcc_suffix}
+fi
+
+%postun
+if [ $1 -eq 0 ] ; then
+  update-alternatives --remove go %{_bindir}/go-%{gcc_suffix}
+fi
+
 %files
 %defattr(-,root,root)
 %{_prefix}/bin/gcc
@@ -516,7 +538,12 @@ EOF
 
 %files -n gcc-go
 %defattr(-,root,root)
-# empty - only for the dependency
+%{_bindir}/gccgo
+%{_bindir}/go
+%{_bindir}/gofmt
+%ghost %{_sysconfdir}/alternatives/go
+%ghost %{_sysconfdir}/alternatives/gofmt
+%doc %{_mandir}/man1/gccgo.1.gz
 
 %if %{separate_bi32}