Fix Java Makefile on Darwin (#936)

* Fixes the logic for Dylib extensions on macOS.
* Adds an uninstall task and documentation.

bindings/java/Makefile

@@ -15,6 +15,9 @@ jar:
 install: lib jar
 	$(MAKE) -f Makefile.build install
 
+uninstall:
+		$(MAKE) -f Makefile.build uninstall
+
 gen_const:
 	cd .. && python const_generator.py java
 

bindings/java/Makefile.build

@@ -15,8 +15,7 @@ SRC := $(shell ls unicorn/*.java)
 OS := $(shell uname)
 ifeq ($(OS),Darwin)
    LIB_EXT=.dylib
-endif
+else ifeq ($(OS),Linux)
-ifeq ($(OS),Linux)
    LIB_EXT=.so
 else
    LIB_EXT=.dll
@@ -67,6 +66,10 @@ install: lib jar
 	cp libunicorn_java$(LIB_EXT) $(JAVA_HOME)/lib/ext
 	cp $(JARFILE) $(JAVA_HOME)/lib/ext
 
+uninstall:
+	rm $(JAVA_HOME)/lib/ext/libunicorn_java$(LIB_EXT)
+	rm $(JAVA_HOME)/lib/ext/$(JARFILE)
+
 gen_const:
 	cd .. && python const_generator.py java
 

bindings/java/README.TXT

@@ -32,3 +32,6 @@ The samples directory contains some sample code to show how to use Unicorn API.
 - SampleNetworkAuditing.java
   Unicorn sample for auditing network connection and file handling in shellcode.
 
+To uninstall Java binding for Unicorn:
+
+   $ sudo make uninstall