diff --git a/mkpkgconfig b/mkpkgconfig
index 0ae2a24bf9..1897e3ce5c 100755
--- a/mkpkgconfig
+++ b/mkpkgconfig
@@ -7,6 +7,13 @@ if [ "x$ASTERISKVERSIONNUM" = "x" ]; then
   exit
 fi
 
+if uname -a | grep -q Darwin
+then
+  SEDARG=-E
+else
+  SEDARG=-r
+fi
+
 ## Create a pkgconfig spec file for 3rd party modules (pkg-config asterisk --cflags)
 
 if [ ! -d $PPATH ]; then
@@ -16,10 +23,10 @@ fi
 ## Clean out CFLAGS for the spec file.
 
 LOCAL_CFLAGS=`echo $CFLAGS | sed -e 's/\s*-pipe\s*//g' | sed -e 's/-[Wmp]\S*\s*//g' | \
-  sed -r -e 's/-I(include|\.\.\/include) //g' | \
+  sed $SEDARG -e 's/-I(include|\.\.\/include) //g' | \
   sed -e 's/-DINSTALL_PREFIX=\S* //g' | \
-  sed -r -e 's/-DASTERISK_VERSION=\S* //g' | \
-  sed -r -e 's/-DAST(ETCDIR|LIBDIR|VARLIBDIR|VARRUNDIR|SPOOLDIR|LOGDIR|CONFPATH|MODDIR|AGIDIR)=\S* //g'`
+  sed $SEDARG -e 's/-DASTERISK_VERSION=\S* //g' | \
+  sed $SEDARG -e 's/-DAST(ETCDIR|LIBDIR|VARLIBDIR|VARRUNDIR|SPOOLDIR|LOGDIR|CONFPATH|MODDIR|AGIDIR)=\S* //g'`
 
 
 cat <<EOF > $PPATH/asterisk.pc