此参数会影响到库生成后的存放位置，影响生成位置的应该是相关平台下的变量PRODUCT_PACKAGES
http://blog.csdn.net/evilcode/article/details/6459299
LOCAL_MODULE_TAGS ：=user eng tests optional
user: 指该模块只在user版本下才编译
eng: 指该模块只在eng版本下才编译
tests: 指该模块只在tests版本下才编译
optional:指该模块在所有版本下都编译
eng This is the default flavor. A plain "make" is the same as "make eng". droid is an alias for eng.
* Installs modules tagged with: eng, debug, user, and/or development.
* Installs non-APK modules that have no tags specified.
* Installs APKs according to the product definition files, in addition to tagged APKs.
* ro.secure=0
* ro.debuggable=1
* ro.kernel.android.checkjni=1
* adb is enabled by default.
user "make user" This is the flavor intended to be the final release bits.
* Installs modules tagged with user.
* Installs non-APK modules that have no tags specified.
* Installs APKs according to the product definition files; tags are ignored for APK modules.
* ro.secure=1
* ro.debuggable=0
* adb is disabled by default.
userdebug "make userdebug" The same as user, except:
* Also installs modules tagged with debug.
* ro.debuggable=1
* adb is enabled by default.
Build flavors/types
When building for a particular product, it's often useful to have minor variations on what is ultimately the final release build. These are the currently-defined "flavors" or "types" (we need to settle on a real name for these).
eng |
This is the default flavor. A plain "make " is the same as "make eng ". droid is an alias for eng .
|
user |
"make user "
This is the flavor intended to be the final release bits.
|
userdebug |
"make userdebug "
The same as
|
If you build one flavor and then want to build another, you should run "make installclean " between the two makes to guarantee that you don't pick up files installed by the previous flavor. "make clean " will also suffice, but it takes a lot longer.
Android 编译重要参数 LOCAL_MODULE_TAGS
最近移植tslib库到android系统，发现编译好的库和测试工具竟然没有输入到out/target/product/Ok6410/system/lib 和 out/target/product/Ok6410/system/bin下面，感觉很奇怪，于是下定决心看一下，到底输入到了哪里。
过程如下：
tslib的源代码放到了android2.3 源代码下 vendor 目录 （android2.3中自己添加，如何设置自己的vendor 我的博客中有说明）forlinx/OK6410/的下面. tslib目录下面的 Android.mk写好以后，重新make clean 整个android源码，再次make 编译通过，奇怪的是输出目录 out/target/product/Ok6410/system/bin 下面竟然没有tslib相关的工具，而是放在了out/target/product/OK6410/symbols/system/bin 下面，在做打包文件时，由于没有把symbols文件夹放到文件系统里面，所以校准功能不能实现。（事实上提取文件系统过程中也不应该把symbols文件夹考虑在内）。
最后查找原因 ，是因为tslib文件下的Android.mk文件里面，LOCAL_MODULE_TAGS变量设置的有问题。
LOCAL_MODULE_TAGS :=optional
把这项改为
LOCAL_MODULE_TAGS :=eng即可
原因是LOCAL_MODULE_TAGS 变量跟TARGET_BUILD_VARIANT 变量息息相关。 android系统编译时如果不指定
TARGET_BUILD_VARIANT 变量的值，默认 TARGET_BUILD_VARIANT=eng ，这一项指定 编译android时形成的版本风格，一般发布时使用这个值,当然还有user,debuguser等风格值，具体看一下这个链接http://android.git.kernel.org/?p=platform/build.git;a=blob_plain;f=core/build-system.html;h=43bae03b6b7b9cba678b86d2faf424fa565497bf;hb=HEAD，如果打不开，翻个墙就可以。
这样设置好以后，重新编译，输出目录out/target/product/Ok6410/system/bin ,out/target/product/Ok6410/system/lib里面就有tslib 相关的库和测试程序了。
所以，如果自己需要加额外的模块，或者应用程序，一定要注意Android.mk里面的这个变量，当然了，如果你指定了LOCAL_MODULE_TAGS :=optional,也能编译出来，但是存放的输入路径就不是一般的
out/target/product/Ok6410/system/目录了，而是out/target/product/OK6410/symbols/system/目录。
后来自己在android源代码的 external目录下面放了一个模块，指定该模块的编译风格为LOCAL_MODULE_TAGS :=optional,重新编译，通过以后，竟然直接输出到了out/target/product/Ok6410/system/ 目录，很是惊讶，个人认为还跟模块存放的目录有关.所以无论模块在哪个文件夹下面，最好指定的值跟TARGET_BUILD_VARIANT 相关，如果没指定TARGET_BUILD_VARIANT ，系统会默认设置TARGET_BUILD_VARIANT =eng,你也就指定LOCAL_MODULE_TAGS :=eng
目前自己遇到的 vendor目录，hardware目录下面的模块输出路径跟LOCAL_MODULE_TAGS 有很大的关系
LOCAL_MODULE_TAGS :=optional >> out/target/product/OK6410/symbols/system/
LOCAL_MODULE_TAGS :=eng >> out/target/product/Ok6410/system/
当然前提是TARGET_BUILD_VARIANT=eng .
下面是网友遇到的类似问题：
"Set LOCAL_MODULE_TAGS to any number of whitespace-separated tags.
This variable controls what build flavors the package gets included
in. For example:
* user: include this in user/userdebug builds
* eng: include this in eng builds
* tests: the target is a testing target and makes it available for tests
* optional: don't include this"
Are these the same as "variants" and if so, which name would affect
the build and how? I've noticed that everything mentioned in a
product's makefile will always get built. But what gets in the final
system.img not always the same as what gets built.
http://groups.google.com.tw/group/android-platform/browse_thread/thread/a4f70254a2ceb622
http://android.git.kernel.org/?p=platform/build.git;a=blob_plain;f=core/build-system.html;h=43bae03b6b7b9cba678b86d2faf424fa565497bf;hb=HEAD
以上是自己在移植android2.3过程中发现的一个问题，如果您也遇到了，并且认为我的解释存在问题，请指出，以免给大家带来误解。
