Reconfig libc's Android.mk to build for multilib

1. Moved arch-specific setup to their own files:
    - <arch>/<arch>.mk, arch-specific configs. Variables in those config
      end with the arch name.
    - removed the extra complexity introduced by function libc-add-cpu-variant-src,
      which seems to be not very useful these days.
2. Separated out the crt object files generation rules and set up the
   rules for both TARGET_ARCH and TARGET_2ND_ARCH.
3. Build all the libraries for both TARGET_ARCH and TARGET_2ND_ARCH,
  with the arch-specific LOCAL_ variables.

Bug: 11654773
Change-Id: I9c2d85db0affa49199d182236d2210060a321421

libc/crt.mk

@@ -0,0 +1,149 @@
+# Define the libc run-time (crt) support object files that must be built,
+# which are needed to build all other objects (shared/static libs and
+# executables)
+# ==========================================================================
+# AArch64, ARM, MIPS, and x86 all need crtbegin_so/crtend_so.
+#
+# For x86, the .init section must point to a function that calls all
+# entries in the .ctors section. (on ARM this is done through the
+# .init_array section instead).
+#
+# For all the platforms, the .fini_array section must point to a function
+# that will call __cxa_finalize(&__dso_handle) in order to ensure that
+# static C++ destructors are properly called on dlclose().
+#
+# Args:
+#     my_2nd_arch_prefix: set to $(TARGET_2ND_ARCH_VAR_PREFIX) if it's
+#                         for the 2nd arch; otherwise empty.
+
+my_arch := $(TARGET_$(my_2nd_arch_prefix)ARCH)
+
+my_libc_crt_target_crtbegin_file := $(libc_crt_target_crtbegin_file_$(my_arch))
+my_libc_crt_target_crtbegin_so_file := $(libc_crt_target_crtbegin_so_file_$(my_arch))
+
+my_libc_crt_target_cflags := \
+    $(libc_crt_target_cflags) \
+    $(libc_crt_target_cflags_$(my_arch))
+
+my_libc_crt_target_so_cflags := \
+    $(libc_crt_target_so_cflags_$(my_arch)) \
+    $(my_libc_crt_target_cflags)
+
+my_libc_crt_target_ldflags := $(libc_crt_target_ldflags_$(my_arch))
+
+
+# See the comment in crtbrand.c for the reason why we need to generate
+# crtbrand.s before generating crtbrand.o.
+GEN := $($(my_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/crtbrand.s
+$(GEN): PRIVATE_CC := $($(my_2nd_arch_prefix)TARGET_CC)
+$(GEN): PRIVATE_CFLAGS := $(my_libc_crt_target_so_cflags)
+$(GEN): $(LOCAL_PATH)/bionic/crtbrand.c
+	@mkdir -p $(dir $@)
+	$(hide) $(PRIVATE_CC) $(PRIVATE_CFLAGS) -S \
+		-MD -MF $(@:%.s=%.d) -o $@ $<
+	$(hide) sed -i -e '/\.note\.ABI-tag/s/progbits/note/' $@
+	$(call transform-d-to-p-args,$(@:%.s=%.d),$(@:%.s=%.P))
+-include $(GEN:%.s=%.P)
+
+
+GEN := $($(my_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/crtbrand.o
+$(GEN): PRIVATE_CC := $($(my_2nd_arch_prefix)TARGET_CC)
+$(GEN): PRIVATE_CFLAGS := $(my_libc_crt_target_so_cflags)
+$(GEN): $($(my_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/crtbrand.s
+	@mkdir -p $(dir $@)
+	$(hide) $(PRIVATE_CC) $(PRIVATE_CFLAGS) -o $@ -c $<
+
+
+GEN := $($(my_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/crtbegin_so.o
+$(GEN): PRIVATE_CC := $($(my_2nd_arch_prefix)TARGET_CC)
+$(GEN): PRIVATE_CFLAGS := $(my_libc_crt_target_so_cflags)
+$(GEN): $(my_libc_crt_target_crtbegin_so_file)
+	@mkdir -p $(dir $@)
+	$(hide) $(PRIVATE_CC) $(PRIVATE_CFLAGS) \
+		-MD -MF $(@:%.o=%.d) -o $@ -c $<
+	$(transform-d-to-p)
+-include $(GEN:%.o=%.P)
+
+
+GEN := $($(my_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/crtend_so.o
+$(GEN): PRIVATE_CC := $($(my_2nd_arch_prefix)TARGET_CC)
+$(GEN): PRIVATE_CFLAGS := $(my_libc_crt_target_so_cflags)
+$(GEN): $(LOCAL_PATH)/arch-common/bionic/crtend_so.S
+	@mkdir -p $(dir $@)
+	$(hide) $(PRIVATE_CC) $(PRIVATE_CFLAGS) \
+		-MD -MF $(@:%.o=%.d) -o $@ -c $<
+	$(transform-d-to-p)
+-include $(GEN:%.o=%.P)
+
+
+# The following two are installed to device
+GEN := $($(my_2nd_arch_prefix)TARGET_OUT_SHARED_LIBRARIES)/crtbegin_so.o
+$(GEN): $($(my_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/crtbegin_so.o
+	$(hide) mkdir -p $(dir $@) && cp -f $< $@
+ALL_GENERATED_SOURCES += $(GEN)
+
+GEN := $($(my_2nd_arch_prefix)TARGET_OUT_SHARED_LIBRARIES)/crtend_so.o
+$(GEN): $($(my_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/crtend_so.o
+	$(hide) mkdir -p $(dir $@) && cp -f $< $@
+ALL_GENERATED_SOURCES += $(GEN)
+
+
+GEN := $($(my_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/crtbegin_static1.o
+$(GEN): PRIVATE_CC := $($(my_2nd_arch_prefix)TARGET_CC)
+$(GEN): PRIVATE_CFLAGS := $(my_libc_crt_target_cflags)
+$(GEN): $(my_libc_crt_target_crtbegin_file)
+	@mkdir -p $(dir $@)
+	$(hide) $(PRIVATE_CC) $(PRIVATE_CFLAGS) \
+		-MD -MF $(@:%.o=%.d) -o $@ -c $<
+	$(transform-d-to-p)
+-include $(GEN:%.o=%.P)
+
+
+GEN := $($(my_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/crtbegin_static.o
+$(GEN): PRIVATE_LD := $($(my_2nd_arch_prefix)TARGET_LD)
+$(GEN): PRIVATE_LDFLAGS := $(my_libc_crt_target_ldflags)
+$(GEN): $($(my_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/crtbegin_static1.o \
+    $($(my_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/crtbrand.o
+	@mkdir -p $(dir $@)
+	$(hide) $(PRIVATE_LD) $(PRIVATE_LDFLAGS) -r -o $@ $^
+
+
+GEN := $($(my_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/crtbegin_dynamic1.o
+$(GEN): PRIVATE_CC := $($(my_2nd_arch_prefix)TARGET_CC)
+$(GEN): PRIVATE_CFLAGS := $(my_libc_crt_target_cflags)
+$(GEN): $(my_libc_crt_target_crtbegin_file)
+	@mkdir -p $(dir $@)
+	$(hide) $(PRIVATE_CC) $(PRIVATE_CFLAGS) \
+		-MD -MF $(@:%.o=%.d) -o $@ -c $<
+	$(transform-d-to-p)
+-include $(GEN:%.o=%.P)
+
+
+GEN := $($(my_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/crtbegin_dynamic.o
+$(GEN): PRIVATE_LD := $($(my_2nd_arch_prefix)TARGET_LD)
+$(GEN): PRIVATE_LDFLAGS := $(my_libc_crt_target_ldflags)
+$(GEN): $($(my_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/crtbegin_dynamic1.o \
+    $($(my_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/crtbrand.o
+	@mkdir -p $(dir $@)
+	$(hide) $(PRIVATE_LD) $(PRIVATE_LDFLAGS) -r -o $@ $^
+
+
+# We rename crtend.o to crtend_android.o to avoid a
+# name clash between gcc and bionic.
+GEN := $($(my_2nd_arch_prefix)TARGET_OUT_INTERMEDIATE_LIBRARIES)/crtend_android.o
+$(GEN): PRIVATE_CC := $($(my_2nd_arch_prefix)TARGET_CC)
+$(GEN): PRIVATE_CFLAGS := $(my_libc_crt_target_cflags)
+$(GEN): $(LOCAL_PATH)/arch-common/bionic/crtend.S
+	@mkdir -p $(dir $@)
+	$(hide) $(PRIVATE_CC) $(PRIVATE_CFLAGS) \
+		-MD -MF $(@:%.o=%.d) -o $@ -c $<
+	$(transform-d-to-p)
+-include $(GEN:%.o=%.P)
+
+# Clear temp vars
+my_libc_crt_target_ldflags :=
+my_libc_crt_target_so_cflags :=
+my_libc_crt_target_cflags :=
+my_libc_crt_target_crtbegin_so_file :=
+my_libc_crt_target_crtbegin_file :=
+my_arch :=