base-linux: add ARM support

This patch introduces a new platform 'linux_arm' for building and running
Genode/Linux on an ARM device.

Known limitations:

- libc 'setjmp()'/'longjmp()' doesn't currently save/restore floating
  point registers

Fixes #746.

base-linux/lib/import/import-lx_hybrid.mk

@@ -97,8 +97,12 @@ USE_HOST_LD_SCRIPT = yes
 ifeq (x86_64,$(findstring x86_64,$(SPECS)))
 CXX_LINK_OPT += -Wl,--dynamic-linker=/lib64/ld-linux-x86-64.so.2
 else
+ifeq (arm,$(findstring arm,$(SPECS)))
+CXX_LINK_OPT += -Wl,--dynamic-linker=/lib/ld-linux.so.3
+else
 CXX_LINK_OPT += -Wl,--dynamic-linker=/lib/ld-linux.so.2
 endif
+endif
 
 # because we use the host compiler's libgcc, omit the Genode toolchain's version
 LD_LIBGCC =

base-linux/lib/import/import-syscall.mk

@@ -1,9 +1,9 @@
 HOST_INC_DIR += $(dir $(call select_from_repositories,src/platform/linux_syscalls.h))
 HOST_INC_DIR += /usr/include
 
-# needed for Ubuntu 11.04
+# needed for Ubuntu >= 11.04
+HOST_INC_DIR += /usr/include/$(shell gcc -dumpmachine)
 HOST_INC_DIR += /usr/include/i386-linux-gnu
-HOST_INC_DIR += /usr/include/x86_64-linux-gnu
 
 #
 # Some header files installed on GNU/Linux test for the GNU compiler. For

base-linux/lib/mk/arm/base.mk

@@ -0,0 +1,8 @@
+include $(REP_DIR)/lib/mk/base.inc
+
+LIBS += startup cxx
+
+SRC_CC += thread.cc thread_linux.cc
+
+vpath thread.cc      $(BASE_DIR)/src/base/thread
+vpath thread_linux.cc $(REP_DIR)/src/base/thread

base-linux/lib/mk/arm/startup.mk

@@ -0,0 +1,5 @@
+LIBS += syscall
+
+include $(BASE_DIR)/lib/mk/startup.inc
+
+vpath crt0.s $(REP_DIR)/src/platform/arm

base-linux/lib/mk/arm/syscall.mk

@@ -0,0 +1,5 @@
+REQUIRES = linux arm
+SRC_S   += lx_clone.S lx_syscall.S
+
+vpath lx_clone.S   $(REP_DIR)/../base-linux/src/platform/arm
+vpath lx_syscall.S $(REP_DIR)/../base-linux/src/platform/arm