runtime: add the --without-libatomic configure option

This adds the --without-libatomic configure option, which is useful for building libgo
with a non-gcc compiler.

It disables libgo's dependency on libatomic. This
is useful for platforms where it is known that the libatomic runtime
functions are not required, or where the compiler automatically
provides an implementation of them.

From-SVN: r211065

libgo/Makefile.am

@@ -30,6 +30,8 @@ toolexeclibgodir = $(nover_glibgo_toolexeclibdir)/go/$(gcc_version)/$(target_ali
 LIBFFI = @LIBFFI@
 LIBFFIINCS = @LIBFFIINCS@
 
+LIBATOMIC = @LIBATOMIC@
+
 WARN_CFLAGS = $(WARN_FLAGS) $(WERROR)
 
 # -I/-D flags to pass when compiling.
@@ -1949,8 +1951,7 @@ libgo_la_LDFLAGS = \
 
 libgo_la_LIBADD = \
 	$(libgo_go_objs) ../libbacktrace/libbacktrace.la \
-	../libatomic/libatomic_convenience.la \
-	$(LIBFFI) $(PTHREAD_LIBS) $(MATH_LIBS) $(NET_LIBS)
+	$(LIBATOMIC) $(LIBFFI) $(PTHREAD_LIBS) $(MATH_LIBS) $(NET_LIBS)
 
 libgobegin_a_SOURCES = \
 	runtime/go-main.c

libgo/Makefile.in

@@ -171,10 +171,9 @@ am__DEPENDENCIES_2 = bufio.lo bytes.lo bytes/index.lo crypto.lo \
 	testing/iotest.lo testing/quick.lo unicode/utf16.lo \
 	unicode/utf8.lo
 libgo_la_DEPENDENCIES = $(am__DEPENDENCIES_2) \
-	../libbacktrace/libbacktrace.la \
-	../libatomic/libatomic_convenience.la $(am__DEPENDENCIES_1) \
+	../libbacktrace/libbacktrace.la $(am__DEPENDENCIES_1) \
 	$(am__DEPENDENCIES_1) $(am__DEPENDENCIES_1) \
-	$(am__DEPENDENCIES_1)
+	$(am__DEPENDENCIES_1) $(am__DEPENDENCIES_1)
 @LIBGO_IS_LINUX_FALSE@am__objects_1 = lock_sema.lo thread-sema.lo
 @LIBGO_IS_LINUX_TRUE@am__objects_1 = lock_futex.lo thread-linux.lo
 @HAVE_SYS_MMAN_H_FALSE@am__objects_2 = mem_posix_memalign.lo
@@ -316,6 +315,7 @@ INSTALL_SCRIPT = @INSTALL_SCRIPT@
 INSTALL_STRIP_PROGRAM = @INSTALL_STRIP_PROGRAM@
 LD = @LD@
 LDFLAGS = @LDFLAGS@
+LIBATOMIC = @LIBATOMIC@
 LIBFFI = @LIBFFI@
 LIBFFIINCS = @LIBFFIINCS@
 LIBOBJS = @LIBOBJS@
@@ -2020,8 +2020,7 @@ libgo_la_LDFLAGS = \
 
 libgo_la_LIBADD = \
 	$(libgo_go_objs) ../libbacktrace/libbacktrace.la \
-	../libatomic/libatomic_convenience.la \
-	$(LIBFFI) $(PTHREAD_LIBS) $(MATH_LIBS) $(NET_LIBS)
+	$(LIBATOMIC) $(LIBFFI) $(PTHREAD_LIBS) $(MATH_LIBS) $(NET_LIBS)
 
 libgobegin_a_SOURCES = \
 	runtime/go-main.c

libgo/configure

@@ -676,6 +676,7 @@ LIBGO_IS_FREEBSD_TRUE
 LIBGO_IS_DARWIN_FALSE
 LIBGO_IS_DARWIN_TRUE
 go_include
+LIBATOMIC
 LIBFFIINCS
 LIBFFI
 nover_glibgo_toolexeclibdir
@@ -817,6 +818,7 @@ enable_libtool_lock
 enable_werror
 enable_version_specific_runtime_libs
 with_libffi
+with_libatomic
 with_system_libunwind
 enable_sjlj_exceptions
 '
@@ -1469,6 +1471,7 @@ Optional Packages:
   --with-pic              try to use only PIC/non-PIC objects [default=use
                           both]
   --without-libffi        don't use libffi
+  --without-libatomic     don't use libatomic
   --with-system-libunwind use installed libunwind
 
 Some influential environment variables:
@@ -11115,7 +11118,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11118 "configure"
+#line 11121 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -11221,7 +11224,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11224 "configure"
+#line 11227 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -13483,6 +13486,24 @@ fi
 
 
 
+# See if the user wants to configure without libatomic. This is useful if we are
+# on an architecture for which libgo does not need an atomic support library and
+# libatomic does not support our C compiler.
+
+# Check whether --with-libatomic was given.
+if test "${with_libatomic+set}" = set; then :
+  withval=$with_libatomic; :
+else
+  with_libatomic=${with_libatomic_default-yes}
+fi
+
+
+LIBATOMIC=
+if test "$with_libatomic" != no; then
+   LIBATOMIC=../libatomic/libatomic_convenience.la
+fi
+
+
 # Used to tell GNU make to include a file without telling automake to
 # include it.
 go_include="-include"

libgo/configure.ac

@@ -122,6 +122,21 @@ fi
 AC_SUBST(LIBFFI)
 AC_SUBST(LIBFFIINCS)
 
+# See if the user wants to configure without libatomic. This is useful if we are
+# on an architecture for which libgo does not need an atomic support library and
+# libatomic does not support our C compiler.
+AC_ARG_WITH(libatomic,
+  AS_HELP_STRING([--without-libatomic],
+                 [don't use libatomic]),
+  [:],
+  [with_libatomic=${with_libatomic_default-yes}])
+
+LIBATOMIC=
+if test "$with_libatomic" != no; then
+   LIBATOMIC=../libatomic/libatomic_convenience.la
+fi
+AC_SUBST(LIBATOMIC)
+
 # Used to tell GNU make to include a file without telling automake to
 # include it.
 go_include="-include"

libgo/testsuite/Makefile.in

@@ -96,6 +96,7 @@ INSTALL_SCRIPT = @INSTALL_SCRIPT@
 INSTALL_STRIP_PROGRAM = @INSTALL_STRIP_PROGRAM@
 LD = @LD@
 LDFLAGS = @LDFLAGS@
+LIBATOMIC = @LIBATOMIC@
 LIBFFI = @LIBFFI@
 LIBFFIINCS = @LIBFFIINCS@
 LIBOBJS = @LIBOBJS@