Use target.linux for all linux kernel based targets

Now in Android.bp files, target.linux applies to all targets running a
linux kernel (android, linux_glibc, linux_bionic). So common
flags/sources/etc can be combined instead of copying them to each
target.

Test: m
Change-Id: If7ad138ea1c540c160731f86b6ccc0daa5c69b83
diff --git a/libbacktrace/Android.bp b/libbacktrace/Android.bp
index 2f20684..03bd128 100644
--- a/libbacktrace/Android.bp
+++ b/libbacktrace/Android.bp
@@ -83,20 +83,7 @@
         darwin: {
             enabled: true,
         },
-        linux_glibc: {
-            srcs: libbacktrace_sources,
-
-            shared_libs: [
-                "libbase",
-                "liblog",
-                "libunwind",
-                "libunwindstack",
-            ],
-
-            static_libs: ["libcutils"],
-        },
-        linux_bionic: {
-            enabled: true,
+        linux: {
             srcs: libbacktrace_sources,
 
             shared_libs: [
@@ -109,16 +96,7 @@
             static_libs: ["libcutils"],
         },
         android: {
-            srcs: libbacktrace_sources,
-
-            shared_libs: [
-                "libbase",
-                "liblog",
-                "libunwind",
-                "libunwindstack",
-            ],
-
-            static_libs: ["libasync_safe", "libcutils"],
+            static_libs: ["libasync_safe"],
         },
     },
     whole_static_libs: ["libdemangle"],
@@ -135,13 +113,7 @@
     srcs: ["backtrace_testlib.cpp"],
 
     target: {
-        linux_glibc: {
-            shared_libs: [
-                "libunwind",
-                "libunwindstack",
-            ],
-        },
-        android: {
+        linux: {
             shared_libs: [
                 "libunwind",
                 "libunwindstack",