ignore build directories for CMake
diff --git a/.gitignore b/.gitignore
index b7abb38..0f12b41 100644
--- a/.gitignore
+++ b/.gitignore
@@ -90,6 +90,9 @@
 *.VC.db
 *.VC.opendb
 
+# CMake build directories
+build*/
+
 # Xcode
 xcode/Capstone.xcodeproj/xcuserdata
 xcode/Capstone.xcodeproj/project.xcworkspace/xcuserdata