diff --git a/makeGcc b/makeGcc
index 03a5720..f78fd12 100755
--- a/makeGcc
+++ b/makeGcc
@@ -3,7 +3,7 @@
 # =========                 |
 # \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
 #  \\    /   O peration     |
-#   \\  /    A nd           | Copyright (C) 2016-2017 OpenCFD Ltd.
+#   \\  /    A nd           | Copyright (C) 2016-2019 OpenCFD Ltd.
 #    \\/     M anipulation  |
 #------------------------------------------------------------------------------
 #                           | Copyright (C) 2011-2016 OpenFOAM Foundation
@@ -63,6 +63,7 @@ usage() {
 usage: ${0##*/} [OPTION] [gcc-VERSION] [gmp-VERSION] [mpfr-VERSION] [mpc-VERSION]
 options:
   -clang            Force clang/clang++ for building
+  -m32 | -m64       32-bit or 64-bit (default) ABI
   -multilib         for 64-bit systems with 32-bit support required
   -no-multilib      for 64-bit systems without 32-bit support (DEFAULT)
   -no-threadsafe    disable mpfr thread-safe (default is auto-detect)
@@ -79,6 +80,8 @@ USAGE
     exit 1
 }
 #------------------------------------------------------------------------------
+optArch=64      # Use 64-bit ABI
+
 # Build 32-bit libraries on 64-bit systems (normally not needed)
 optMultilib=disable
 unset optThreadSafe # unset=auto
@@ -94,6 +97,9 @@ do
         export CXX=clang++
         ;;
 
+    -m32 | -m64)
+        optArch="${1#*m}"
+        ;;
     -multi*)
         optMultilib=enable
         ;;
@@ -136,6 +142,7 @@ cat<<SUMMARY
 GCC configuration
 ------------------
     GCC     = $gccPACKAGE
+    ABI     = $optArch
     GMP     = $gmpPACKAGE
     MPFR    = $mpfrPACKAGE
     MPC     = $mpcPACKAGE
@@ -144,17 +151,6 @@ Using CC    = $CC $CFLAGS
 Using CXX   = $CXX $CXXFLAGS
 SUMMARY
 
-# Set 32 or 64 bit ABI
-case "$WM_ARCH_OPTION" in
-32 | 64)
-    ABI=$WM_ARCH_OPTION
-    ;;
-*)
-    die "The WM_ARCH_OPTION ($WM_ARCH_OPTION) must be 32 or 64"
-    ;;
-esac
-
-
 #------------------------------------------------------------------------------
 # Build/install without compiler name
 buildBASE=$WM_THIRD_PARTY_DIR/build/$WM_ARCH$WM_COMPILER_ARCH
@@ -204,7 +200,7 @@ else
     cd $buildDIR
 
     set -x
-    $sourceDIR/configure ABI=$ABI \
+    $sourceDIR/configure ABI=$optArch \
         --prefix=$GMP_ARCH_PATH \
         --libdir=$GMP_ARCH_PATH/lib$WM_COMPILER_LIB_ARCH \
         --enable-cxx \
@@ -234,7 +230,7 @@ fi
 # Build MPFR
 # ================
 echo "---------------"
-if [ -d $MPFR_ARCH_PATH ]
+if [ -d "$MPFR_ARCH_PATH" ]
 then
     echo "Already built: $mpfrPACKAGE"
 elif _foamIsSystem $MPFR_ARCH_PATH
@@ -260,7 +256,7 @@ else
     [ -n "$optThreadSafe" ] && configOpt="--${optThreadSafe}-thread-safe"
 
     set -x
-    $sourceDIR/configure ABI=$ABI \
+    $sourceDIR/configure ABI=$optArch \
         --prefix=$MPFR_ARCH_PATH \
         --libdir=$MPFR_ARCH_PATH/lib$WM_COMPILER_LIB_ARCH \
         $configGMP $configOpt \
@@ -290,7 +286,7 @@ fi
 # Build MPC
 # ================
 echo "---------------"
-if [ -d $MPC_ARCH_PATH ]
+if [ -d "$MPC_ARCH_PATH" ]
 then
     echo "Already built: $mpcPACKAGE"
 elif _foamIsSystem $MPC_ARCH_PATH
@@ -312,7 +308,7 @@ else
     cd $buildDIR
 
     set -x
-    $sourceDIR/configure ABI=$ABI \
+    $sourceDIR/configure ABI=$optArch \
         --prefix=$MPC_ARCH_PATH \
         --libdir=$MPC_ARCH_PATH/lib$WM_COMPILER_LIB_ARCH \
         $configGMP $configMPFR \
@@ -346,7 +342,7 @@ fi
 # or specify -no-multilib on the command-line
 #
 echo "---------------"
-if [ -d $GCC_ARCH_PATH ]
+if [ -d "$GCC_ARCH_PATH" ]
 then
     echo "Already built: $gccPACKAGE"
 elif _foamIsSystem $GCC_ARCH_PATH