android: fix LLVM version string related building errors

Adding \ prior to " in llvm version string fixes the following building errors:

external/mesa/src/gallium/drivers/r600/r600_pipe_common.c:1290:14:
error: expected ')'
                 ", LLVM " MESA_LLVM_VERSION_STRING
                           ^
<command line>:8:34: note: expanded from here
                                 ^
external/mesa/src/gallium/drivers/r600/r600_pipe_common.c:1287:10:
note: to match this '('
        snprintf(rscreen->renderer_string, sizeof(rscreen->renderer_string),
                ^
1 error generated.

Fixes: 05b114e ("simplify LLVM version string printing")
Signed-off-by: Mauro Rossi <issor.oruam@gmail.com>
Reviewed-by: Eric Engestrom <eric@engestrom.ch>
diff --git a/Android.mk b/Android.mk
index 8662bfb..3b9a540 100644
--- a/Android.mk
+++ b/Android.mk
@@ -97,13 +97,13 @@
   $(if $(filter $(MESA_ANDROID_MAJOR_VERSION), 4 5), \
     $(warning Unsupported LLVM version in Android $(MESA_ANDROID_MAJOR_VERSION)),) \
   $(if $(filter 6,$(MESA_ANDROID_MAJOR_VERSION)), \
-    $(eval LOCAL_CFLAGS += -DHAVE_LLVM=0x0307 -DMESA_LLVM_VERSION_STRING="3.7")) \
+    $(eval LOCAL_CFLAGS += -DHAVE_LLVM=0x0307 -DMESA_LLVM_VERSION_STRING=\"3.7\")) \
   $(if $(filter 7,$(MESA_ANDROID_MAJOR_VERSION)), \
-    $(eval LOCAL_CFLAGS += -DHAVE_LLVM=0x0308 -DMESA_LLVM_VERSION_STRING="3.8")) \
+    $(eval LOCAL_CFLAGS += -DHAVE_LLVM=0x0308 -DMESA_LLVM_VERSION_STRING=\"3.8\")) \
   $(if $(filter 8,$(MESA_ANDROID_MAJOR_VERSION)), \
-    $(eval LOCAL_CFLAGS += -DHAVE_LLVM=0x0309 -DMESA_LLVM_VERSION_STRING="3.9")) \
+    $(eval LOCAL_CFLAGS += -DHAVE_LLVM=0x0309 -DMESA_LLVM_VERSION_STRING=\"3.9\")) \
   $(if $(filter P,$(MESA_ANDROID_MAJOR_VERSION)), \
-    $(eval LOCAL_CFLAGS += -DHAVE_LLVM=0x0309 -DMESA_LLVM_VERSION_STRING="3.9")) \
+    $(eval LOCAL_CFLAGS += -DHAVE_LLVM=0x0309 -DMESA_LLVM_VERSION_STRING=\"3.9\")) \
   $(eval LOCAL_SHARED_LIBRARIES += libLLVM)
 endef