libgo patch committed: set runtime.GOROOT at build time

[Ian Lance Taylor via Gcc-patches]

This patch changes libto to set runtime.GOROOT value at build time.
In Go 1.17 the gc toolchain changed to set runtime.GOROOT in cmd/link
(previously it was runtime/internal/sys.GOROOT).  This patch does the
same in libgo.  Bootstrapped and ran Go testsuite on
x86_64-pc-linux-gnu.  Committed to mainline.

Ian

gotools:
* Makefile.am (check-runtime): Add goroot.go to --extrafiles.
* Makefile.in: Regenerate.

9a5c82b7c1cd935c4a35d6dd532a2aa3356d6785
diff --git a/gcc/go/gofrontend/MERGE b/gcc/go/gofrontend/MERGE
index e2abd5fc4b7..edfbe46d8f4 100644
--- a/gcc/go/gofrontend/MERGE
+++ b/gcc/go/gofrontend/MERGE
@@ -1,4 +1,4 @@
-850235e4b974b9c5c2d7a1f9860583bd07f2a45c
+e3bfc0889237a5bb8aa7ae30e1cff14f90a5f941
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.
diff --git a/gotools/Makefile.am b/gotools/Makefile.am
index 6576fe77b85..199899b9ef0 100644
--- a/gotools/Makefile.am
+++ b/gotools/Makefile.am
@@ -245,14 +245,14 @@ check-runtime: go$(EXEEXT) $(noinst_PROGRAMS) check-head 
check-gccgo check-gcc
        export LD_LIBRARY_PATH; \
        GOARCH=`$(abs_builddir)/go$(EXEEXT) env GOARCH`; \
        GOOS=`$(abs_builddir)/go$(EXEEXT) env GOOS`; \
-       files=`$(SHELL) $(libgosrcdir)/../match.sh --goarch=$${GOARCH} 
--goos=$${GOOS} --srcdir=$(libgosrcdir)/runtime 
--extrafiles="$(libgodir)/runtime_linknames.go $(libgodir)/runtime_sysinfo.go 
$(libgodir)/sigtab.go" --tag=libffi`; \
+       files=`$(SHELL) $(libgosrcdir)/../match.sh --goarch=$${GOARCH} 
--goos=$${GOOS} --srcdir=$(libgosrcdir)/runtime 
--extrafiles="$(libgodir)/runtime_linknames.go $(libgodir)/runtime_sysinfo.go 
$(libgodir)/sigtab.go $(libgodir)/goroot.go" --tag=libffi`; \
        echo "$(ECHO_ENV) GC='$(abs_builddir)/check-gccgo 
-fgo-compiling-runtime' GOARCH=$${GOARCH} GOOS=$${GOOS} $(SHELL) 
$(libgosrcdir)/../testsuite/gotest --goarch=$${GOARCH} --goos=$${GOOS} 
--basedir=$(libgosrcdir)/.. --srcdir=$(libgosrcdir)/runtime --pkgpath=runtime 
--pkgfiles='$${files}' $(GOTESTFLAGS) -test.timeout=$(GOTOOLS_TEST_TIMEOUT)s 
-test.v" > runtime-testlog
        $(CHECK_ENV) \
        GC="$${GCCGO} -fgo-compiling-runtime"; \
        export GC; \
        GOARCH=`$(abs_builddir)/go$(EXEEXT) env GOARCH`; \
        GOOS=`$(abs_builddir)/go$(EXEEXT) env GOOS`; \
-       files=`$(SHELL) $(libgosrcdir)/../match.sh --goarch=$${GOARCH} 
--goos=$${GOOS} --srcdir=$(libgosrcdir)/runtime 
--extrafiles="$(libgodir)/runtime_linknames.go $(libgodir)/runtime_sysinfo.go 
$(libgodir)/sigtab.go" --tag=libffi`; \
+       files=`$(SHELL) $(libgosrcdir)/../match.sh --goarch=$${GOARCH} 
--goos=$${GOOS} --srcdir=$(libgosrcdir)/runtime 
--extrafiles="$(libgodir)/runtime_linknames.go $(libgodir)/runtime_sysinfo.go 
$(libgodir)/sigtab.go $(libgodir)/goroot.go" --tag=libffi`; \
        $(SHELL) $(libgosrcdir)/../testsuite/gotest --goarch=$${GOARCH} 
--goos=$${GOOS} --basedir=$(libgosrcdir)/.. --srcdir=$(libgosrcdir)/runtime 
--pkgpath=runtime --pkgfiles="$${files}" $(GOTESTFLAGS) 
-test.timeout=$(GOTOOLS_TEST_TIMEOUT)s -test.v >> runtime-testlog 2>&1 || echo 
"--- $${fl}: go test runtime (0.00s)" >> runtime-testlog
        grep '^--- ' runtime-testlog | sed -e 's/^--- \(.*\) ([^)]*)$$/\1/' | 
sort -k 2
 
diff --git a/libgo/Makefile.am b/libgo/Makefile.am
index 92fedcf6eb8..5c377a30df9 100644
--- a/libgo/Makefile.am
+++ b/libgo/Makefile.am
@@ -545,6 +545,14 @@ s-gcpu: Makefile
        $(SHELL) $(srcdir)/mvifdiff.sh gcpugen.go.tmp gcpugen.go
        $(STAMP) $@
 
+goroot.go: s-goroot; @true
+s-goroot: Makefile
+       rm -f goroot.go.tmp
+       echo "package runtime" > goroot.go.tmp
+       echo 'var defaultGOROOT = `$(prefix)`' >> goroot.go.tmp
+       $(SHELL) $(srcdir)/mvifdiff.sh goroot.go.tmp goroot.go
+       $(STAMP) $@
+
 buildcfg.go: s-buildcfg; @true
 s-buildcfg: Makefile
        rm -f buildcfg.go.tmp
@@ -1005,7 +1013,8 @@ math_lo_GOCFLAGS = $(MATH_FLAG)
 math_check_GOCFLAGS = $(MATH_FLAG)
 
 # Add generated files to the runtime package.
-extra_go_files_runtime = runtime_linknames.go runtime_sysinfo.go sigtab.go
+extra_go_files_runtime = \
+       runtime_linknames.go runtime_sysinfo.go sigtab.go goroot.go
 runtime.lo.dep: $(extra_go_files_runtime)
 
 # Add generated files to the syscall package.
diff --git a/libgo/go/runtime/extern.go b/libgo/go/runtime/extern.go
index 0d7f3577913..6bd612fcf32 100644
--- a/libgo/go/runtime/extern.go
+++ b/libgo/go/runtime/extern.go
@@ -211,8 +211,6 @@ func Caller(skip int) (pc uintptr, file string, line int, 
ok bool)
 // program counter adjustment.
 func Callers(skip int, pc []uintptr) int
 
-var defaultGOROOT string // set by cmd/link
-
 // GOROOT returns the root of the Go tree. It uses the
 // GOROOT environment variable, if set at process start,
 // or else the root used during the Go build.