Provisioning: build cmake from source on macOS 10.13

Change-Id: Ifada0cf62d1e75e8cab3e3bbe6250718747d0703
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

coin/provisioning/common/unix/install_cmake.sh

@@ -57,14 +57,16 @@ sudo rm "$targetFile"
 
 echo "Configuring and building cmake"
 cd "$targetDir"
-if uname -a |grep -qv Darwin; then
+if uname -a |grep -q Darwin; then
+    ./bootstrap --prefix="$(xcrun --sdk macosx --show-sdk-path)/usr/local"
+    SetEnvVar PATH "\$PATH:$(xcrun --sdk macosx --show-sdk-path)/usr/local/bin"
+else
     ./bootstrap --prefix="$cmakeHome"
-    make
-    make install
+    SetEnvVar "PATH" "$cmakeHome/bin:\$PATH"
 fi
+make
+sudo make install
 
 sudo rm -r "$targetDir"
 
-SetEnvVar "PATH" "$cmakeHome/bin:\$PATH"
-
 echo "CMake = $version" >> ~/versions.txt