[Fix] Correct dependency for building libhphp_java.so

Summary:
The java .so is built from PIC_OBJECTS now, so the dependency should be from
PIC_OBJECTS. Otherwise, we might compile the .cpp file before generating the .h
file.

Quite a few libcore build failures seemed to be due to this problem.

Task ID: #

Test Plan:
make -C ffi/java

Reviewed By: mwilliams
Reviewers: mwilliams
CC: ps, mwilliams
Revert Plan:
Tags:

- begin *PUBLIC* platform impact section -
Bugzilla: #
- end platform impact -

Differential Revision: 236510

src/ffi/java/Makefile

@@ -20,6 +20,7 @@ TARGETS = $(SHARED_LIB)
 all : $(CLS) $(HEADER) $(TARGETS)
 
 $(OBJECTS) : $(HEADER)
+$(PIC_OBJECTS) : $(HEADER)
 
 JAVA_PATH = /usr/local/jdk-6u7-64