diff -Nurp pacman-4.0.1/etc/makepkg.conf pacman-4.0.1/etc/makepkg.conf
--- pacman-4.0.1/etc/makepkg.conf	2011-12-28 16:46:26.715892832 +0100
+++ pacman-4.0.1/etc/makepkg.conf	2011-12-28 16:48:43.499352501 +0100
@@ -33,6 +33,9 @@ CHOST="x86_64-unknown-linux-gnu"
 #-- Make Flags: change this for DistCC/SMP systems
 #MAKEFLAGS="-j2"
 
+# Run makepkg with a differnt nice level
+#NICE="5"
+
 #########################################################################
 # BUILD ENVIRONMENT
 #########################################################################
diff -Nurp pacman-4.0.1/etc/makepkg.conf.in pacman-4.0.1/etc/makepkg.conf.in
--- pacman-4.0.1/etc/makepkg.conf.in	2011-12-28 16:46:26.715892832 +0100
+++ pacman-4.0.1/etc/makepkg.conf.in	2011-12-28 16:48:56.752371247 +0100
@@ -33,6 +33,9 @@ CHOST="@CHOST@"
 #-- Make Flags: change this for DistCC/SMP systems
 #MAKEFLAGS="-j2"
 
+# Run makepkg with a differnt nice level
+#NICE="5"
+
 #########################################################################
 # BUILD ENVIRONMENT
 #########################################################################
diff -Nurp pacman-4.0.1/scripts/makepkg.sh.in pacman-4.0.1/scripts/makepkg.sh.in
--- pacman-4.0.1/scripts/makepkg.sh.in	2011-12-28 16:46:26.755891899 +0100
+++ pacman-4.0.1/scripts/makepkg.sh.in	2011-12-28 16:51:58.268061107 +0100
@@ -2066,6 +2066,7 @@ set -E
 [[ -n ${PKGEXT} ]] && _PKGEXT=${PKGEXT}
 [[ -n ${SRCEXT} ]] && _SRCEXT=${SRCEXT}
 [[ -n ${GPGKEY} ]] && _GPGKEY=${GPGKEY}
+[[ -n ${NICE} ]] && _NICE=${NICE}
 
 # default config is makepkg.conf
 MAKEPKG_CONF=${MAKEPKG_CONF:-$confdir/makepkg.conf}
@@ -1981,6 +1981,12 @@ if [[ $MAKEPKG_CONF = "$confdir/makepkg.
 	source ~/.makepkg.conf
 fi
 
+# Renice makepkg itself if defined in configuration
+NICE=${_NICE:-$NICE}
+if [[ -n "${NICE}" ]]; then
+	renice -n "${NICE}" $$ >/dev/null
+fi
+
 # set pacman command if not already defined
 PACMAN=${PACMAN:-pacman}