Fix shared library install target dependency (#3057)

b/335757361

Currently we need to run
`ninja -C out/raspi-2_debug cobalt ; ninja -C out/raspi-2_debug
cobalt_install`
to build an installable target.

This change fixes the install target build dependency so that
`cobalt_install` depends on `cobalt` for modular installable targets
so that we just need to run `ninja -C out/raspi-2_debug cobalt_install`
to get an installable binary.

(cherry picked from commit 25df9d7)

cobalt/site/docs/development/setup-raspi.md

@@ -86,21 +86,21 @@ Raspberry Pi.
     following command:
 
     ```
-    $ cobalt/build/gn.py -p raspi-2
+    $ cobalt/build/gn.py -p raspi-2 -C devel
     ```
 
 1.  Compile the code from the `cobalt/` directory:
 
     ```
-    $ ninja -C out/raspi-2_debug cobalt
+    $ ninja -C out/raspi-2_devel cobalt_install
     ```
 
 1.  Run the following command to install your Cobalt binary (and content)
     on the device:
 
     ```
     $ rsync -avzLPh --exclude="obj*" --exclude="gen/" \
-          $COBALT_SRC/out/raspi-2_debug pi@$RASPI_ADDR:~/
+          $COBALT_SRC/out/raspi-2_devel pi@$RASPI_ADDR:~/
     ```
 
     The `rsyncs` get somewhat faster after the first time, as `rsync` is good at
@@ -112,8 +112,8 @@ Raspberry Pi.
 
     ```
     $ ssh pi@$RASPI_ADDR
-    $ cd raspi-2_debug
-    $ ./cobalt
+    $ cd raspi-2_devel/install/cobalt_loader
+    $ ./cobalt_loader
     ```
 
     With this approach, you can just hit `[CTRL-C]` to close Cobalt. If you

starboard/build/config/BUILDCONFIG.gn

@@ -611,7 +611,10 @@ template("shared_library") {
       not_needed([ "installable_target_dep" ])
       type = "shared_library"
 
-      deps = []
+      # When we build "{target_name}_install", we expect all files
+      # needed for a working target to be present.
+      deps = [ ":${actual_target_name}" ]
+
       if (defined(invoker.deps)) {
         deps += invoker.deps
       }