Fix Android.mk files for plugins on darwin.

Darwin uses a few different flags for this than Linux, and we missed this
when we updated the test builds recently.

Change-Id: I8a0e8bc18ef698a0ed933f96b2bce0653f4307e5
(cherry picked from commit 651de8d5ac0b28b10ad0259efc75cf6152dc13dc)
diff --git a/lib/Transforms/Hello/Android.mk b/lib/Transforms/Hello/Android.mk
index e2d6163..6a09237 100644
--- a/lib/Transforms/Hello/Android.mk
+++ b/lib/Transforms/Hello/Android.mk
@@ -13,6 +13,10 @@
 LOCAL_SRC_FILES := $(transforms_hello_SRC_FILES)
 LOCAL_MODULE:= LLVMHello
 
+ifeq ($(HOST_OS),darwin)
+LOCAL_LDFLAGS := -Wl,-undefined -Wl,dynamic_lookup
+endif
+
 LOCAL_MODULE_TAGS := optional
 
 include $(LLVM_HOST_BUILD_MK)
diff --git a/tools/bugpoint-passes/Android.mk b/tools/bugpoint-passes/Android.mk
index 51b35c7..bd09c69 100644
--- a/tools/bugpoint-passes/Android.mk
+++ b/tools/bugpoint-passes/Android.mk
@@ -15,6 +15,9 @@
 
 LOCAL_MODULE_TAGS := optional
 LOCAL_MODULE_CLASS := SHARED_LIBRARIES # needed for tblgen
+ifeq ($(HOST_OS),darwin)
+LOCAL_LDFLAGS := -Wl,-undefined -Wl,dynamic_lookup
+endif
 
 include $(LLVM_HOST_BUILD_MK)
 include $(LLVM_GEN_INTRINSICS_MK)
diff --git a/tools/bugpoint/Android.mk b/tools/bugpoint/Android.mk
index 752972a..393851f 100644
--- a/tools/bugpoint/Android.mk
+++ b/tools/bugpoint/Android.mk
@@ -52,7 +52,11 @@
 LOCAL_STATIC_LIBRARIES := $(bugpoint_STATIC_LIBRARIES)
 
 LOCAL_LDLIBS += -lpthread -lm -ldl
+ifeq ($(HOST_OS),darwin)
+LOCAL_LDFLAGS += -Wl,-export_dynamic
+else
 LOCAL_LDFLAGS += -Wl,--export-dynamic
+endif
 
 include $(LLVM_ROOT_PATH)/llvm.mk
 include $(LLVM_HOST_BUILD_MK)
diff --git a/tools/opt/Android.mk b/tools/opt/Android.mk
index 3c6a494..4c8997a 100644
--- a/tools/opt/Android.mk
+++ b/tools/opt/Android.mk
@@ -76,7 +76,11 @@
 LOCAL_SRC_FILES := $(llvm_opt_SRC_FILES)
 LOCAL_STATIC_LIBRARIES := $(llvm_opt_STATIC_LIBRARIES)
 LOCAL_LDLIBS += -lpthread -lm -ldl
+ifeq ($(HOST_OS),darwin)
+LOCAL_LDFLAGS += -Wl,-export_dynamic
+else
 LOCAL_LDFLAGS += -Wl,--export-dynamic
+endif
 
 include $(LLVM_ROOT_PATH)/llvm.mk
 include $(LLVM_HOST_BUILD_MK)