Flesh out the logging implementation.

Add PLOG and ensure we have CHECK_STREQ and CHECK_STRNE to go with
the existing non-functional DCHECK_STREQ and DCHECK_STRNE.

This also gives us two different logging implementations, one for
the host that just uses std::cerr, and one for Android that uses
the Android log.

Also bring in the StringPrintf family.

Change-Id: I8e190c2c58f26b22ee76a2a87d447df6eb0fa73b
diff --git a/build/Android.common.mk b/build/Android.common.mk
index bf442a3..ac9553e 100644
--- a/build/Android.common.mk
+++ b/build/Android.common.mk
@@ -50,15 +50,18 @@
 	src/raw_dex_file.cc \
 	src/runtime.cc \
 	src/stringpiece.cc \
+	src/stringprintf.cc \
 	src/thread.cc
 
 LIBART_TARGET_SRC_FILES := \
 	$(LIBART_COMMON_SRC_FILES) \
-	src/assembler_arm.cc
+	src/assembler_arm.cc \
+	src/logging_android.cc
 
 LIBART_HOST_SRC_FILES := \
 	$(LIBART_COMMON_SRC_FILES) \
-	src/assembler_x86.cc
+	src/assembler_x86.cc \
+	src/logging_linux.cc
 
 TEST_COMMON_SRC_FILES := \
 	src/class_linker_test.cc \