Allow parallel make ("make -j2") by giving make the opportunity to

determine dependencies.

As in subdirectory foo/bar, $(top_builddir)/foo/bar is defined to be the
current directory, this does not cause any regressions.

From Hans Ulrich Niedermann (hun@n-dimensional.de)

simgear/bucket/Makefile.am

@@ -11,7 +11,7 @@ libsgbucket_a_SOURCES = newbucket.cxx
 # testbucket_SOURCES = testbucket.cxx
 
 # testbucket_LDADD = \
-# 	$(top_builddir)/bucket/libsgbucket.a \
+# 	libsgbucket.a \
 # 	$(top_builddir)/misc/libsgmisc.a
 
 INCLUDES = -I$(top_srcdir)

simgear/io/Makefile.am

@@ -27,7 +27,7 @@ noinst_PROGRAMS = decode_binobj socktest lowtest tcp_server tcp_client
 tcp_server_SOURCES = tcp_server.cxx
 
 tcp_server_LDADD = \
-	$(top_builddir)/simgear/io/libsgio.a \
+	libsgio.a \
 	$(top_builddir)/simgear/debug/libsgdebug.a \
 	$(top_builddir)/simgear/bucket/libsgbucket.a \
 	$(top_builddir)/simgear/misc/libsgmisc.a \
@@ -38,7 +38,7 @@ tcp_server_LDADD = \
 tcp_client_SOURCES = tcp_client.cxx
 
 tcp_client_LDADD = \
-	$(top_builddir)/simgear/io/libsgio.a \
+	libsgio.a \
 	$(top_builddir)/simgear/debug/libsgdebug.a \
 	$(top_builddir)/simgear/bucket/libsgbucket.a \
 	$(top_builddir)/simgear/misc/libsgmisc.a \
@@ -49,7 +49,7 @@ tcp_client_LDADD = \
 socktest_SOURCES = socktest.cxx
 
 socktest_LDADD = \
-	$(top_builddir)/simgear/io/libsgio.a \
+	libsgio.a \
 	$(top_builddir)/simgear/debug/libsgdebug.a \
 	$(top_builddir)/simgear/bucket/libsgbucket.a \
 	$(top_builddir)/simgear/misc/libsgmisc.a \
@@ -60,7 +60,7 @@ socktest_LDADD = \
 lowtest_SOURCES = lowtest.cxx
 
 lowtest_LDADD = \
-	$(top_builddir)/simgear/io/libsgio.a \
+	libsgio.a \
 	$(top_builddir)/simgear/debug/libsgdebug.a \
 	$(top_builddir)/simgear/bucket/libsgbucket.a \
 	$(top_builddir)/simgear/misc/libsgmisc.a \
@@ -69,7 +69,7 @@ lowtest_LDADD = \
 decode_binobj_SOURCES = decode_binobj.cxx
 
 decode_binobj_LDADD = \
-	$(top_builddir)/simgear/io/libsgio.a \
+	libsgio.a \
 	$(top_builddir)/simgear/debug/libsgdebug.a \
 	$(top_builddir)/simgear/bucket/libsgbucket.a \
 	$(top_builddir)/simgear/misc/libsgmisc.a \

simgear/magvar/Makefile.am

@@ -13,7 +13,7 @@ noinst_PROGRAMS = testmagvar
 testmagvar_SOURCES = testmagvar.cxx
 
 testmagvar_LDADD = \
-	$(top_builddir)/simgear/magvar/libsgmagvar.a \
+	libsgmagvar.a \
 	$(base_LIBS)
 
 INCLUDES = -I$(top_srcdir)

simgear/misc/Makefile.am

@@ -26,10 +26,16 @@ noinst_PROGRAMS = tabbed_value_test swap_test
 
 tabbed_value_test_SOURCES = tabbed_values_test.cxx
 tabbed_value_test_LDADD = \
-	$(top_builddir)/simgear/misc/libsgmisc.a \
+	libsgmisc.a \
 	$(top_builddir)/simgear/xml/libsgxml.a \
 	$(top_builddir)/simgear/debug/libsgdebug.a
 
+$(top_builddir)/simgear/xml/libsgxml.a:
+	cd $(top_builddir)/simgear/xml && $(MAKE) $(AM_MAKEFLAGS) libsgxml.a
+
+$(top_builddir)/simgear/debug/libsgdebug.a:
+	cd $(top_builddir)/simgear/debug && $(MAKE) $(AM_MAKEFLAGS) libsgdebug.a
+
 swap_test_SOURCES = swap_test.cpp
 
 INCLUDES = -I$(top_srcdir)

simgear/props/Makefile.am

@@ -16,7 +16,7 @@ noinst_PROGRAMS = props_test
 
 props_test_SOURCES = props_test.cxx
 props_test_LDADD = \
-	$(top_builddir)/simgear/props/libsgprops.a \
+	libsgprops.a \
 	$(top_builddir)/simgear/xml/libsgxml.a \
 	$(top_builddir)/simgear/misc/libsgmisc.a \
 	$(top_builddir)/simgear/debug/libsgdebug.a \

simgear/route/Makefile.am

@@ -15,7 +15,7 @@ noinst_PROGRAMS = waytest routetest
 waytest_SOURCES = waytest.cxx
 
 waytest_LDADD = \
-	$(top_builddir)/simgear/route/libsgroute.a \
+	libsgroute.a \
 	$(top_builddir)/simgear/math/libsgmath.a \
 	$(top_builddir)/simgear/debug/libsgdebug.a \
 	$(top_builddir)/simgear/misc/libsgmisc.a \
@@ -28,7 +28,7 @@ waytest_LDADD = \
 routetest_SOURCES = routetest.cxx
 
 routetest_LDADD = \
-	$(top_builddir)/simgear/route/libsgroute.a \
+	libsgroute.a \
 	$(top_builddir)/simgear/math/libsgmath.a \
 	$(top_builddir)/simgear/debug/libsgdebug.a \
 	$(base_LIBS)

simgear/screen/Makefile.am

@@ -41,7 +41,7 @@ noinst_PROGRAMS = TestRenderTexture
 TestRenderTexture_SOURCES = TestRenderTexture.cpp
 
 TestRenderTexture_LDADD = \
-	$(top_builddir)/simgear/screen/libsgscreen.a \
+	libsgscreen.a \
 	$(top_builddir)/simgear/debug/libsgdebug.a \
 	$(opengl_LIBS)
 endif

simgear/serial/Makefile.am

@@ -11,7 +11,7 @@ noinst_PROGRAMS = testserial
 testserial_SOURCES = testserial.cxx
 
 testserial_LDADD = \
-	$(top_builddir)/simgear/serial/libsgserial.a \
+	libsgserial.a \
 	$(top_builddir)/simgear/debug/libsgdebug.a
 
 INCLUDES = -I$(top_srcdir)

simgear/sound/Makefile.am

@@ -26,7 +26,7 @@ openal_test1_LDADD = \
 	$(openal_LIBS)
 
 openal_test2_LDADD = \
-	$(top_builddir)/simgear/sound/libsgsound.a \
+	libsgsound.a \
 	$(top_builddir)/simgear/debug/libsgdebug.a \
 	$(top_builddir)/simgear/misc/libsgmisc.a \
 	$(top_builddir)/simgear/structure/libsgstructure.a \