libphobos: Fix link build errors when compiling with unsupported options

The first compilation test to get baseline warnings was getting more
messages due to a missing object.d file, compared to later configure
tests where libphobos is in the include paths.

Because there must always be an object module during compilation, let
the tests themselves be an empty object module instead.

libphobos/ChangeLog:

2019-04-24  Iain Buclaw  <ibuclaw@gdcproject.org>

	PR d/88431
	* configure: Regenerate.
	* m4/libtool.m4 (lt_simple_compile_test_code): Update to not have
	dependencies on libphobos.
	(lt_simple_link_test_code): Likewise.
	(GDCFLAGS): Don't override for D compiler tests.

From-SVN: r270531

libphobos/ChangeLog

 2019-04-24  Iain Buclaw  <ibuclaw@gdcproject.org>
 
+	PR d/88431
+	* configure: Regenerate.
+	* m4/libtool.m4 (lt_simple_compile_test_code): Update to not have
+	dependencies on libphobos.
+	(lt_simple_link_test_code): Likewise.
+	(GDCFLAGS): Don't override for D compiler tests.
+
+2019-04-24  Iain Buclaw  <ibuclaw@gdcproject.org>
+
 	* configure.tgt: Add aarch64*-*-linux* as a supported target.
 
 2019-04-23  Iain Buclaw  <ibuclaw@gdcproject.org>

libphobos/configure

@@ -11981,10 +11981,16 @@ objext=o
 objext_D=$objext
 
 # Code to be used in simple compile tests
-lt_simple_compile_test_code="module mod; extern(C) int main() { return 0; }"
+lt_simple_compile_test_code="\
+  module object;
+  shared int some_variable = 0;
+"
 
 # Code to be used in simple link tests
-lt_simple_link_test_code='module mod; extern(C) int main() { return 0; }'
+lt_simple_link_test_code="\
+  module object;
+  extern(C) int main() { return 0; }
+"
 
 # ltmain only uses $CC for tagged configurations so make sure $CC is set.
 
@@ -12020,12 +12026,9 @@ $RM -r conftest*
 # Allow CC to be a program name with arguments.
 lt_save_CC=$CC
 lt_save_CFLAGS=$CFLAGS
-lt_save_DFLAGS=$GDCFLAGS
 lt_save_GCC=$GCC
 GCC=yes
 CC=${GDC-"gdc"}
-# Need to specify location for object.d
-GDCFLAGS="-nophoboslib $GDCFLAGS"
 CFLAGS=$GDCFLAGS
 compiler=$CC
 compiler_D=$CC
@@ -13867,7 +13870,6 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 GCC=$lt_save_GCC
 CC=$lt_save_CC
 CFLAGS=$lt_save_CFLAGS
-GDCFLAGS=$lt_save_DFLAGS
 
   GDCFLAGS=$gdc_save_DFLAGS
 

libphobos/m4/libtool.m4

@@ -20,10 +20,16 @@ objext=o
 _LT_TAGVAR(objext, $1)=$objext
 
 # Code to be used in simple compile tests
-lt_simple_compile_test_code="module mod; extern(C) int main() { return 0; }"
+lt_simple_compile_test_code="\
+  module object;
+  shared int some_variable = 0;
+"
 
 # Code to be used in simple link tests
-lt_simple_link_test_code='module mod; extern(C) int main() { return 0; }'
+lt_simple_link_test_code="\
+  module object;
+  extern(C) int main() { return 0; }
+"
 
 # ltmain only uses $CC for tagged configurations so make sure $CC is set.
 _LT_TAG_COMPILER
@@ -35,12 +41,9 @@ _LT_LINKER_BOILERPLATE
 # Allow CC to be a program name with arguments.
 lt_save_CC=$CC
 lt_save_CFLAGS=$CFLAGS
-lt_save_DFLAGS=$GDCFLAGS
 lt_save_GCC=$GCC
 GCC=yes
 CC=${GDC-"gdc"}
-# Need to specify location for object.d
-GDCFLAGS="-nophoboslib $GDCFLAGS"
 CFLAGS=$GDCFLAGS
 compiler=$CC
 _LT_TAGVAR(compiler, $1)=$CC
@@ -74,5 +77,4 @@ AC_LANG_RESTORE
 GCC=$lt_save_GCC
 CC=$lt_save_CC
 CFLAGS=$lt_save_CFLAGS
-GDCFLAGS=$lt_save_DFLAGS
 ])# _LT_LANG_D_CONFIG