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
diff --git a/libc/arch-mips64/mips64.mk b/libc/arch-mips64/mips64.mk
index 19be126..6977d6a 100644
--- a/libc/arch-mips64/mips64.mk
+++ b/libc/arch-mips64/mips64.mk
@@ -1,4 +1,42 @@
-_LIBC_ARCH_COMMON_SRC_FILES := \
+# mips64 specific configs
+
+libc_common_src_files_mips64 := \
+  bionic/memchr.c \
+  bionic/memcmp.c \
+  bionic/memmove.c \
+  bionic/memrchr.c \
+  bionic/strchr.cpp \
+  bionic/strnlen.c \
+  string/bcopy.c \
+  string/index.c \
+  string/strcat.c \
+  string/strcmp.c \
+  string/strcpy.c \
+  string/strlcat.c \
+  string/strlcpy.c \
+  string/strncat.c \
+  string/strncmp.c \
+  string/strncpy.c \
+  string/strrchr.c \
+  upstream-freebsd/lib/libc/string/wcscat.c \
+  upstream-freebsd/lib/libc/string/wcschr.c \
+  upstream-freebsd/lib/libc/string/wcscmp.c \
+  upstream-freebsd/lib/libc/string/wcscpy.c \
+  upstream-freebsd/lib/libc/string/wcslen.c \
+  upstream-freebsd/lib/libc/string/wcsrchr.c \
+  upstream-freebsd/lib/libc/string/wmemcmp.c \
+
+# Fortify implementations of libc functions.
+libc_common_src_files_mips64 += \
+    bionic/__memcpy_chk.cpp \
+    bionic/__memset_chk.cpp \
+    bionic/__strcpy_chk.cpp \
+    bionic/__strcat_chk.cpp \
+
+
+##########################################
+### CPU specific source files
+libc_bionic_src_files_mips64 := \
     arch-mips64/bionic/__bionic_clone.S \
     arch-mips64/bionic/bzero.S \
     arch-mips64/bionic/_exit_with_stack_teardown.S \
@@ -14,9 +52,31 @@
     arch-mips64/bionic/vfork.S \
 
 # FIXME TODO
-## _LIBC_ARCH_COMMON_SRC_FILES += arch-mips64/string/memcpy.S
-## _LIBC_ARCH_COMMON_SRC_FILES += arch-mips64/string/memset.S
-## _LIBC_ARCH_COMMON_SRC_FILES += arch-mips64/string/mips_strlen.c
-_LIBC_ARCH_COMMON_SRC_FILES += bionic/memcpy.c
-_LIBC_ARCH_COMMON_SRC_FILES += bionic/memset.c
-_LIBC_ARCH_COMMON_SRC_FILES += string/strlen.c
+## libc_bionic_src_files_mips64 += arch-mips64/string/memcpy.S
+## libc_bionic_src_files_mips64 += arch-mips64/string/memset.S
+## libc_bionic_src_files_mips64 += arch-mips64/string/mips_strlen.c
+libc_bionic_src_files_mips64 += bionic/memcpy.c
+libc_bionic_src_files_mips64 += bionic/memset.c
+libc_bionic_src_files_mips64 += string/strlen.c
+
+libc_arch_static_src_files_mips64 :=
+
+libc_arch_dynamic_src_files_mips64 :=
+
+##########################################
+# crt-related
+libc_crt_target_cflags_mips64 := \
+    $($(my_2nd_arch_prefix)TARGET_GLOBAL_CFLAGS) \
+    -I$(LOCAL_PATH)/arch-mips/include
+
+libc_crt_target_crtbegin_file_mips64 := \
+    $(LOCAL_PATH)/arch-mips/bionic/crtbegin.c
+
+libc_crt_target_crtbegin_so_file_mips64 := \
+    $(LOCAL_PATH)/arch-common/bionic/crtbegin_so.c
+
+libc_crt_target_so_cflags_mips64 := \
+    -fPIC
+
+libc_crt_target_ldflags_mips64 := \
+    -melf64ltsmip