Configure standalone bcc compiler to work with plugin libraries.

Bug: 7342767

This change adds support (hidden behind the EXTERNAL_BCC_COMPILER ifdef)
for loading plugin libraries via the external bcc toolchain. The external
bcc compiler loads the named library and will then invoke a customized
rsCompilerDriverInit() from that library.

Change-Id: I07c2ea68be54c2255d36926fd37e395db790ef8f
diff --git a/cpu_ref/rsCpuScript.h b/cpu_ref/rsCpuScript.h
index eeb38bf..4cc9d6d 100644
--- a/cpu_ref/rsCpuScript.h
+++ b/cpu_ref/rsCpuScript.h
@@ -47,7 +47,8 @@
 #endif
 
     bool init(char const *resName, char const *cacheDir,
-              uint8_t const *bitcode, size_t bitcodeSize, uint32_t flags);
+              uint8_t const *bitcode, size_t bitcodeSize, uint32_t flags,
+              char const *bccPluginName = NULL);
     virtual void populateScript(Script *);
 
     virtual void invokeFunction(uint32_t slot, const void *params, size_t paramLength);