Convert the qmake call to use a bash array of parameters

In the previous code version it was impossible to pass parameters to qmake
that contain spaces. As example, a qmake option
  QMAKE_CFLAGS='-march=native -O2 -pipe -g'
led to an error message of qmake
  ***Unknown option -O2
since the shell was breaking the string up into words at the spaces.

build.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 
 # 
 # KLayout Layout Viewer
@@ -500,28 +500,29 @@ $QMAKE -v
 # Force a minimum rebuild because of version info
 touch $CURR_DIR/src/version/version.h
 
-qmake_cmd="$QMAKE $CURR_DIR/src/klayout.pro -recursive \
-  CONFIG+=$CONFIG \
-  RUBYLIBFILE=$RUBYLIBFILE \
-  RUBYINCLUDE=$RUBYINCLUDE \
-  RUBYINCLUDE2=$RUBYINCLUDE2 \
-  RUBYVERSIONCODE=$RUBYVERSIONCODE \
-  HAVE_RUBY=$HAVE_RUBY \
-  PYTHONLIBFILE=$PYTHONLIBFILE \
-  PYTHONINCLUDE=$PYTHONINCLUDE \
-  HAVE_PYTHON=$HAVE_PYTHON \
-  HAVE_QTBINDINGS=$HAVE_QTBINDINGS \
-  HAVE_64BIT_COORD=$HAVE_64BIT_COORD \
-  HAVE_QT5=$HAVE_QT5 \
-  PREFIX='$BIN' \
-  RPATH='$RPATH' \
-  KLAYOUT_VERSION=$KLAYOUT_VERSION \
-  KLAYOUT_VERSION_DATE=$KLAYOUT_VERSION_DATE \
-  KLAYOUT_VERSION_REV=$KLAYOUT_VERSION_REV \
-"
+qmake_options=(
+  -recursive
+  CONFIG+="$CONFIG"
+  RUBYLIBFILE="$RUBYLIBFILE"
+  RUBYINCLUDE="$RUBYINCLUDE"
+  RUBYINCLUDE2="$RUBYINCLUDE2"
+  RUBYVERSIONCODE="$RUBYVERSIONCODE"
+  HAVE_RUBY="$HAVE_RUBY"
+  PYTHONLIBFILE="$PYTHONLIBFILE"
+  PYTHONINCLUDE="$PYTHONINCLUDE"
+  HAVE_PYTHON="$HAVE_PYTHON"
+  HAVE_QTBINDINGS="$HAVE_QTBINDINGS"
+  HAVE_64BIT_COORD="$HAVE_64BIT_COORD"
+  HAVE_QT5="$HAVE_QT5"
+  PREFIX="$BIN"
+  RPATH="$RPATH"
+  KLAYOUT_VERSION="$KLAYOUT_VERSION"
+  KLAYOUT_VERSION_DATE="$KLAYOUT_VERSION_DATE"
+  KLAYOUT_VERSION_REV="$KLAYOUT_VERSION_REV"
+)
 
-echo $qmake_cmd
-$qmake_cmd
+echo $QMAKE "$CURR_DIR/src/klayout.pro" "${qmake_options[@]}"
+$QMAKE "$CURR_DIR/src/klayout.pro" "${qmake_options[@]}"
 
 cd $CURR_DIR
 echo ""