os x -- ensure /usr/local dirs exist before symlinking in

Author: U-CIQDEV\gbazerman

hptool/os-extras/osx/bin/activate-hs

@@ -240,6 +240,10 @@ run() {
     fi
 }
 
+ensureDirectoryExists() {
+    run mkdir -p "$1"
+}
+
 symLink() {
     run rm -rf "$2"
     run ln -sf "$1" "$2"
@@ -280,6 +284,10 @@ fi
 ### Set up /usr
 ###
 
+ensureDirectoryExists /usr/local/bin
+ensureDirectoryExists /usr/local/share/man/man1
+ensureDirectoryExists /usr/local/share/doc
+
 symLinkInto $ghcRoot/usr/bin/* /usr/local/bin
 symLinkInto $ghcRoot/usr/share/man/man1/* /usr/local/share/man/man1
 symLinkInto $ghcRoot/usr/share/doc/ghc /usr/local/share/doc