diff --git a/src/configure b/src/configure
index 101e722a28..45cd4b32f9 100755
--- a/src/configure
+++ b/src/configure
@@ -1368,6 +1368,7 @@ Optional Features:
   --enable-xonx           compile X11 (not Quartz) MrEd for Mac OS X
   --enable-libfw          install Mac OS X frameworks to /Library/Frameworks
   --enable-userfw         install Mac OS X frameworks to ~/Library/Frameworks
+  --enable-macprefix      allow --prefix with a Mac OS X install
 
 Optional Packages:
   --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]
@@ -2011,6 +2012,11 @@ if test "${enable_libfw+set}" = set; then
   enableval=$enable_libfw;
 fi
 
+# Check whether --enable-macprefix was given.
+if test "${enable_macprefix+set}" = set; then
+  enableval=$enable_macprefix;
+fi
+
 
 
 ###### Get OS Type #######
@@ -2071,6 +2077,17 @@ else
   if test "$OS" = "Darwin" ; then
     enable_quartz=yes
     enable_origtree=yes
+    if test "${prefix}" != "NONE" ; then
+      if test "${enable_macprefix}" != "yes" ; then
+        echo "ERROR: --prefix not allowed for a Mac OS X build, unless either"
+        echo "         --enable-xonx is supplied (to create a Unix-style"
+        echo "           build), or "
+        echo "         --enable-macprefix is supplied (to allow a Mac-style"
+        echo "           installation, even though --prefix is normally used"
+        echo "           for Unix-style installations)"
+        exit 1
+      fi
+    fi
   fi
 fi
 
diff --git a/src/mzscheme/configure.ac b/src/mzscheme/configure.ac
index 0bff9d4886..eddd4037bb 100644
--- a/src/mzscheme/configure.ac
+++ b/src/mzscheme/configure.ac
@@ -73,6 +73,7 @@ AC_ARG_ENABLE(noopt,   [  --enable-sdk=<path>     use Mac OS X 10.4 SDK director
 AC_ARG_ENABLE(xonx,    [  --enable-xonx           compile X11 (not Quartz) MrEd for Mac OS X])
 AC_ARG_ENABLE(libfw,   [  --enable-libfw          install Mac OS X frameworks to /Library/Frameworks])
 AC_ARG_ENABLE(libfw,   [  --enable-userfw         install Mac OS X frameworks to ~/Library/Frameworks])
+AC_ARG_ENABLE(macprefix, [  --enable-macprefix      allow --prefix with a Mac OS X install])
 
 
 ###### Get OS Type #######
@@ -133,6 +134,17 @@ else
   if test "$OS" = "Darwin" ; then
     enable_quartz=yes
     enable_origtree=yes
+    if test "${prefix}" != "NONE" ; then
+      if test "${enable_macprefix}" != "yes" ; then
+        echo "ERROR: --prefix not allowed for a Mac OS X build, unless either"
+        echo "         --enable-xonx is supplied (to create a Unix-style"
+        echo "           build), or "
+        echo "         --enable-macprefix is supplied (to allow a Mac-style"
+        echo "           installation, even though --prefix is normally used"
+        echo "           for Unix-style installations)"
+        exit 1
+      fi
+    fi
   fi
 fi