libgo: only build x/sys/cpu/cpu_gccgo.c on x86 systems

The C file has a build tag, but the procedure we use for building C
    files ignores build tags.
    
    This should fix the libgo build on non-x86 systems.
    
    Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/194378

From-SVN: r275544

gcc/go/gofrontend/MERGE

@@ -1,4 +1,4 @@
-17bef47f464983fd8513f88f3f159d28e2423e79
+03fa49394bb4b37453795bef3119e5b40c929aee
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

libgo/Makefile.am

@@ -683,6 +683,12 @@ else
 syscall_lib_clone_lo =
 endif
 
+if LIBGO_IS_X86
+golangorg_x_sys_cpu_gccgo_lo = golang.org/x/sys/cpu_gccgo.lo
+else
+golangorg_x_sys_cpu_gccgo_lo =
+endif
+
 PACKAGES = $(shell cat $(srcdir)/libgo-packages.txt)
 
 libgo_go_objs = \
@@ -700,7 +706,7 @@ libgo_go_objs = \
 	runtime/internal/atomic_c.lo \
 	sync/atomic_c.lo \
 	internal/cpu/cpu_gccgo.lo \
-	golang.org/x/sys/cpu_gccgo.lo
+	$(golangorg_x_sys_cpu_gccgo_lo)
 
 libgo_ldflags = \
 	-version-info $(libtool_VERSION) $(PTHREAD_CFLAGS) $(AM_LDFLAGS)

libgo/Makefile.in

@@ -215,19 +215,20 @@ am_libgotool_a_OBJECTS =
 libgotool_a_OBJECTS = $(am_libgotool_a_OBJECTS)
 LTLIBRARIES = $(toolexeclib_LTLIBRARIES)
 @LIBGO_IS_LINUX_TRUE@am__DEPENDENCIES_1 = syscall/clone_linux.lo
-am__DEPENDENCIES_2 = $(addsuffix .lo,$(PACKAGES)) \
+@LIBGO_IS_X86_TRUE@am__DEPENDENCIES_2 = golang.org/x/sys/cpu_gccgo.lo
+am__DEPENDENCIES_3 = $(addsuffix .lo,$(PACKAGES)) \
 	internal/bytealg/bytealg.lo reflect/makefunc_ffi_c.lo \
 	$(am__DEPENDENCIES_1) syscall/errno.lo syscall/signame.lo \
 	syscall/wait.lo $(golangorg_x_net_lif_lo) \
 	$(golangorg_x_net_route_lo) log/syslog/syslog_c.lo \
 	runtime/internal/atomic_c.lo sync/atomic_c.lo \
-	internal/cpu/cpu_gccgo.lo golang.org/x/sys/cpu_gccgo.lo
-am__DEPENDENCIES_3 =
-am__DEPENDENCIES_4 = $(am__DEPENDENCIES_2) \
-	../libbacktrace/libbacktrace.la $(am__DEPENDENCIES_3) \
-	$(am__DEPENDENCIES_3) $(am__DEPENDENCIES_3) \
-	$(am__DEPENDENCIES_3) $(am__DEPENDENCIES_3)
-libgo_llgo_la_DEPENDENCIES = $(am__DEPENDENCIES_4)
+	internal/cpu/cpu_gccgo.lo $(am__DEPENDENCIES_2)
+am__DEPENDENCIES_4 =
+am__DEPENDENCIES_5 = $(am__DEPENDENCIES_3) \
+	../libbacktrace/libbacktrace.la $(am__DEPENDENCIES_4) \
+	$(am__DEPENDENCIES_4) $(am__DEPENDENCIES_4) \
+	$(am__DEPENDENCIES_4) $(am__DEPENDENCIES_4)
+libgo_llgo_la_DEPENDENCIES = $(am__DEPENDENCIES_5)
 @LIBGO_IS_RTEMS_TRUE@am__objects_1 =  \
 @LIBGO_IS_RTEMS_TRUE@	runtime/rtems-task-variable-add.lo
 am__objects_2 = runtime/aeshash.lo runtime/go-assert.lo \
@@ -254,7 +255,7 @@ libgo_llgo_la_LINK = $(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) \
 	$(LIBTOOLFLAGS) --mode=link $(CCLD) $(AM_CFLAGS) $(CFLAGS) \
 	$(libgo_llgo_la_LDFLAGS) $(LDFLAGS) -o $@
 @GOC_IS_LLGO_TRUE@am_libgo_llgo_la_rpath = -rpath $(toolexeclibdir)
-libgo_la_DEPENDENCIES = $(am__DEPENDENCIES_4)
+libgo_la_DEPENDENCIES = $(am__DEPENDENCIES_5)
 am_libgo_la_OBJECTS = $(am__objects_2)
 libgo_la_OBJECTS = $(am_libgo_la_OBJECTS)
 libgo_la_LINK = $(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) \
@@ -906,6 +907,8 @@ SYSINFO_FLAGS = \
 
 @LIBGO_IS_LINUX_FALSE@syscall_lib_clone_lo = 
 @LIBGO_IS_LINUX_TRUE@syscall_lib_clone_lo = syscall/clone_linux.lo
+@LIBGO_IS_X86_FALSE@golangorg_x_sys_cpu_gccgo_lo = 
+@LIBGO_IS_X86_TRUE@golangorg_x_sys_cpu_gccgo_lo = golang.org/x/sys/cpu_gccgo.lo
 PACKAGES = $(shell cat $(srcdir)/libgo-packages.txt)
 libgo_go_objs = \
 	$(addsuffix .lo,$(PACKAGES)) \
@@ -922,7 +925,7 @@ libgo_go_objs = \
 	runtime/internal/atomic_c.lo \
 	sync/atomic_c.lo \
 	internal/cpu/cpu_gccgo.lo \
-	golang.org/x/sys/cpu_gccgo.lo
+	$(golangorg_x_sys_cpu_gccgo_lo)
 
 libgo_ldflags = \
 	-version-info $(libtool_VERSION) $(PTHREAD_CFLAGS) $(AM_LDFLAGS)

libgo/configure

@@ -662,6 +662,8 @@ GO_SYSCALL_OS_FILE
 GO_LIBCALL_OS_ARCH_FILE
 GO_LIBCALL_OS_FILE
 FUNCTION_DESCRIPTORS
+LIBGO_IS_X86_FALSE
+LIBGO_IS_X86_TRUE
 ALLGOARCHFAMILY
 ALLGOARCH
 GOARCH
@@ -11484,7 +11486,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11487 "configure"
+#line 11489 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -11590,7 +11592,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11593 "configure"
+#line 11595 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -14229,6 +14231,15 @@ esac
 
 
 
+ if test "$GOARCH" = "386" -o "$GOARCH" = "amd64" -o "$GOARCH" = "amd64p32"; then
+  LIBGO_IS_X86_TRUE=
+  LIBGO_IS_X86_FALSE='#'
+else
+  LIBGO_IS_X86_TRUE='#'
+  LIBGO_IS_X86_FALSE=
+fi
+
+
 FUNCTION_DESCRIPTORS=false
 case ${host} in
   rs6000*-*-* | powerpc*-*-*)
@@ -16038,6 +16049,10 @@ if test -z "${LIBGO_IS_BSD_TRUE}" && test -z "${LIBGO_IS_BSD_FALSE}"; then
   as_fn_error $? "conditional \"LIBGO_IS_BSD\" was never defined.
 Usually this means the macro was only invoked conditionally." "$LINENO" 5
 fi
+if test -z "${LIBGO_IS_X86_TRUE}" && test -z "${LIBGO_IS_X86_FALSE}"; then
+  as_fn_error $? "conditional \"LIBGO_IS_X86\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
 if test -z "${USING_SPLIT_STACK_TRUE}" && test -z "${USING_SPLIT_STACK_FALSE}"; then
   as_fn_error $? "conditional \"USING_SPLIT_STACK\" was never defined.
 Usually this means the macro was only invoked conditionally." "$LINENO" 5

libgo/configure.ac

@@ -354,6 +354,8 @@ AC_SUBST(GOARCH)
 AC_SUBST(ALLGOARCH)
 AC_SUBST(ALLGOARCHFAMILY)
 
+AM_CONDITIONAL(LIBGO_IS_X86, test "$GOARCH" = "386" -o "$GOARCH" = "amd64" -o "$GOARCH" = "amd64p32")
+
 FUNCTION_DESCRIPTORS=false
 case ${host} in
   rs6000*-*-* | powerpc*-*-*)