Fix build. (#35)

* Enable GitHub Actions CI for pull requests.
* Fix sentencepiece include directives.

Author: dan-zheng

.github/workflows/build.yml

@@ -1,7 +1,7 @@
 name: Build
 
-# Trigger on push or via manual dispatch.
-on: [push, workflow_dispatch]
+# Trigger on push, pull request, or via manual dispatch.
+on: [push, pull_request, workflow_dispatch]
 
 jobs:
   build:

gemma.cc

@@ -60,7 +60,8 @@
 #include "hwy/aligned_allocator.h"
 #include "hwy/base.h"
 #include "hwy/contrib/thread_pool/thread_pool.h"
-#include "sentencepiece_processor.h"
+// copybara:import_next_line:sentencepiece
+#include "src/sentencepiece_processor.h"
 
 namespace gcpp {
 

gemma.h

@@ -33,7 +33,8 @@
 #include "hwy/aligned_allocator.h"
 #include "hwy/base.h"  // hwy::bfloat16_t
 #include "hwy/contrib/thread_pool/thread_pool.h"
-#include "sentencepiece_processor.h"
+// copybara:import_next_line:sentencepiece
+#include "src/sentencepiece_processor.h"
 
 namespace gcpp {