diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5fd1db851a..d1e832e767 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -119,23 +119,7 @@ jobs:
         run: |
           echo LD_LIBRARY_PATH=`pwd`/lib >> $GITHUB_ENV
 
-          case `uname` in
-            Linux)
-                wxPROC_COUNT=`nproc`
-                ;;
-
-            Darwin)
-                wxPROC_COUNT=`sysctl -n hw.ncpu`
-                ;;
-
-            *)
-                echo "*** Unknown platform: `uname` ***"
-                wxPROC_COUNT=0
-                ;;
-          esac
-
-          ((wxPROC_COUNT++))
-          echo wxPROC_COUNT=$wxPROC_COUNT >> $GITHUB_ENV
+          wxPROC_COUNT=`./build/tools/proc_count.sh`
           echo wxBUILD_ARGS=-j$wxPROC_COUNT >> $GITHUB_ENV
 
           # Setting this variable suppresses "Error retrieving accessibility bus address"
diff --git a/build/tools/proc_count.sh b/build/tools/proc_count.sh
new file mode 100755
index 0000000000..f4a5565ecd
--- /dev/null
+++ b/build/tools/proc_count.sh
@@ -0,0 +1,18 @@
+# This script outputs the number of available processors/cores plus one.
+
+case `uname` in
+    Linux)
+        wxPROC_COUNT=`nproc`
+        ;;
+
+    Darwin)
+        wxPROC_COUNT=`sysctl -n hw.ncpu`
+        ;;
+
+    *)
+        wxPROC_COUNT=0
+        ;;
+esac
+
+((wxPROC_COUNT++))
+echo $wxPROC_COUNT