[Makefile] Unnecessary tabs replaced with spaces

Signed-off-by: Anestis Bechtsoudis <anestis@census-labs.com>

Makefile

diff --git a/Makefile b/Makefile
index b6123d8..60dbbea 100644
--- a/Makefile
+++ b/Makefile
@@ -76,8 +76,8 @@
     # Figure out which crash reporter to use.
     CRASHWRANGLER := third_party/mac
     OS_VERSION := $(shell sw_vers -productVersion)
-	ifneq (,$(findstring 10.12,$(OS_VERSION)))
-		CRASH_REPORT := $(CRASHWRANGLER)/CrashReport_Yosemite.o
+    ifneq (,$(findstring 10.12,$(OS_VERSION)))
+        CRASH_REPORT := $(CRASHWRANGLER)/CrashReport_Yosemite.o
     else ifneq (,$(findstring 10.11,$(OS_VERSION)))
         # El Capitan didn't break compatibility
         CRASH_REPORT := $(CRASHWRANGLER)/CrashReport_Yosemite.o