No, it was right before. Try the /cygdrive form.

Change-Id: Icaee640f0e422890ee705b0cec9ab00ea41985ec
Reviewed-on: https://code-review.googlesource.com/c/re2/+/44228
Reviewed-by: Paul Wankadia <junyer@google.com>
diff --git a/kokoro/cmake.sh b/kokoro/cmake.sh
index 73a88a8..7e355f8 100755
--- a/kokoro/cmake.sh
+++ b/kokoro/cmake.sh
@@ -5,7 +5,7 @@
 
 case "${KOKORO_JOB_NAME}" in
   */windows-*)
-    export PATH+=';C:\Program Files (x86)\CMake\bin'
+    export PATH+=':/cygdrive/c/Program Files/CMake/bin'
     # Pin to Visual Studio 2015, which is the minimum that we support.
     CMAKE_G_A_FLAGS=('-G' 'Visual Studio 14 2015' '-A' 'x64')
     ;;