This script provides an easy way to build Qt5 for both 32 and 64-bit Windows. This script assumes that the Mingw-w64 compilers are installed on the host as well as Perl.

build-qt5

#!/bin/bash

#===========================================
# Download URLs for the required libraries.
#===========================================

# NOTE: if you add a URL here, you also need to add it to the
# $packages_to_build list to ensure the proper order.

declare -A urls=(
  [openssl]="http://www.openssl.org/source/openssl-1.0.1e.tar.gz"
  [icu]="http://download.icu-project.org/files/icu4c/50.1.2/icu4c-50_1_2-src.tgz"
  [qt5]="http://releases.qt-project.org/qt5/5.0.1/single/qt-everywhere-opensource-src-5.0.1.tar.gz"
)

#===================
# End download URLs
#===================

# All of the building takes place in ~/qt5 and all of the
# files are installed to ~/<toolchain> where <toolchain>
# is one of i686-w64-mingw32 or x86_64-w64-mingw32.
script_path=`cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd`
build_path=`echo ~/qt5`
install_path=`echo ~`

# Methods for displaying colored output.
print_debug() { echo -e "\E[1;32m$1\E[0m"; }
print_warning() { echo -e "\E[1;33m$1\E[0m"; }
print_error() { echo -e "\E[1;31m$1\E[0m"; exit 1; }

# Determines if an array contains a certain value.
# - $1 array
# - $2 value
array_contains() {
  local a=(${!1})
  for i in ${a[@]} ; do
    if [ $i = $2 ] ; then
      return 0
    fi
  done
  return 1
}

# Utility method to download a URL if not already in the download cache.
# - $1 download URL
download_archive() {
  mkdir -p cache
  cd cache
    if test -e `basename $1` ; then
      print_debug "'`basename $1`' already exists in cache."
    else
      print_debug "Downloading '`basename $1`'..."
      wget $1
    fi
  cd ..
}

# Extracts the specified archive to the specified directory.
# - $1 the name of the package
# - $2 the architecture being built
extract_archive() {
  if test -d $1-$2 ; then
    print_warning "The directory '$1-$2' already exists. It will be overwritten."
    yes | rm -r $1-$2
  fi
  mkdir -p $1-$2
  cd $1-$2
    print_debug "Extracting '`basename ${urls[$1]}`' to '$1-$2'..."
    tar --strip-components 1 -xf ../cache/`basename ${urls[$1]}`
  cd ..
}

# Additional flags passed to the linker.
static_qt5=

# Build the OpenSSL library.
# - $1 architecture
# - $2 toolchain installation path
build_openssl() {
  local openssl_target=`if [ $1 = i686 ] ; then echo mingw ; else echo mingw64 ; fi`
  ./Configure --cross-compile-prefix=$1-w64-mingw32- --openssldir=$2 $openssl_target
  make
  make install
}

# Build the host copy of ICU (the current directory is expected to
# contain the 'source' directory). The build is skipped if it has completed.
build_icu_host() {
  cp -r source ../icu-host
  local cwd=`pwd`
  cd ../icu-host
    ./configure
    make
    touch 
  cd $cwd
}

# Build the ICU library.
# - $1 architecture
# - $2 toolchain installation path
build_icu() {
  # ICU is unique in that we need to actually have a host build and
  # a target build. Begin with the host build.
  cp -r source source-host
  mv source source-target
  cd source-host
    local host_build=`pwd`
    ./configure
    make
  cd ..
  cd source-target
    # First, apply the two patches to the source directory.
    print_debug "Patching ICU source..."
    cat $script_path/icu4c-50_1_2-crossbuild.patch | patch -p2
    local bit=`if [ $1 = i686 ] ; then echo 32 ; else echo 64 ; fi`
    cat $script_path/icu4c-4_6_1-win$bit.patch | patch -p2
    # Now continue building...
    ./configure --host=$1-w64-mingw32 --prefix=$2 --with-cross-build=$host_build
    make
    make install
  cd ..
}

# Build the Qt5 library.
# - $1 architecture
# - $2 toolchain installation path
build_qt5() {
  ./configure -prefix $2 -opensource -confirm-license -release -nomake demos \
    -nomake examples -xplatform win32-g++ -device-option CROSS_COMPILE=$1-w64-mingw32- \
    -I$2/include -L$2/lib $static_qt5
  make
  make install
}

# By default, we build all packages for all architectures.
packages_to_build=( openssl icu qt5 )
architectures_to_build="i686 x86_64"

# Analyze the command-line arguments.
for i in `seq 1 $#` ; do
  eval arg=\$$i
  case $arg in
    --help)
      print_debug "Usage: $0 [--skip-<package>] [--only-<package>]"
      print_debug "  [--32] [--64] [--static]"
      exit 0
      ;;
    --skip-*)
      if array_contains packages_to_build[@] ${arg:7} ; then
        print_debug "${arg:7} will NOT be built."
        unset packages_to_build[${arg:7}]
      else
        print_error "** Error: no package named ${arg:7}."
      fi
      ;;
    --only-*)
      if array_contains packages_to_build[@] ${arg:7} ; then
        print_debug "Only building ${arg:7}."
        packages_to_build=${arg:7}
      else
        print_error "** Error: no package named ${arg:7}."
      fi
      ;;
    --32)
      print_debug "Only building for i686."
      architectures_to_build=i686
      ;;
    --64)
      print_debug "Only building for x86_64."
      architectures_to_build=x86_64
      ;;
    --static)
      print_debug "Qt5 will build static libraries."
      static_qt5="-static"
      ;;
    *)
      print_error "** Error: unrecognized option '$arg'."
  esac
done

mkdir -p $build_path
cd $build_path

# Loop over each package and perform the build steps.
for package in $packages_to_build; do
  download_archive ${urls[$package]}
  # Each step below is done twice - once for each architecture.
  for architecture in $architectures_to_build; do
    extract_archive $package $architecture
    cd $package-$architecture
      # Invoke the build command for this package.
      print_debug "Building $package..."
      eval build_$package $architecture $install_path/$architecture-w64-mingw32
    cd ..
  done
done

print_debug "All packages have finished building."

icu4c-4_6_1-win32.patch

--- icu/source/config/mh-mingw	2011-05-25 02:59:51.523815290 +0200
+++ icu/source/config/mh-mingw	2011-05-25 02:57:58.715695508 +0200
@@ -133,7 +133,7 @@
 LDLIBRARYPATH_ENVVAR = PATH
 
 # The type of assembly to write for generating an object file
-GENCCODE_ASSEMBLY=-a gcc-cygwin
+GENCCODE_ASSEMBLY=-a gcc-mingw-x86
 
 # These are needed to allow the pkgdata GNU make files to work
 PKGDATA_DEFS = -DU_MAKE=\"$(MAKE)\"

icu4c-4_6_1-win64.patch

--- icu/source/config/mh-mingw	2011-05-25 02:59:51.523815290 +0200
+++ icu/source/config/mh-mingw	2011-05-25 02:57:58.715695508 +0200
@@ -133,7 +133,7 @@
 LDLIBRARYPATH_ENVVAR = PATH
 
 # The type of assembly to write for generating an object file
-GENCCODE_ASSEMBLY=-a gcc-cygwin
+GENCCODE_ASSEMBLY=-a gcc-mingw-x64
 
 # These are needed to allow the pkgdata GNU make files to work
 PKGDATA_DEFS = -DU_MAKE=\"$(MAKE)\"

icu4c-50_1_2-crossbuild.patch

--- icu/source/config/icu-config-bottom	2013-01-11 01:23:56.000000000 +0100
+++ icu/source/config/icu-config-bottom	2013-01-24 17:32:54.452298936 +0100
@@ -3,7 +3,7 @@
 ## Copyright (c) 2002-2011, International Business Machines Corporation and
 ## others. All Rights Reserved.
 
-ICUUC_FILE="${libdir}/${ICULIBS_COMMON_LIB_NAME}"
+ICUUC_FILE="${bindir}/${ICULIBS_COMMON_LIB_NAME}"
 ICUUC_FILE_A="${libdir}/${ICULIBS_COMMON_LIB_NAME_A}"
     
 #  echo ENABLE RPATH $ENABLE_RPATH and RPATHLDFLAGS=${RPATH_LDFLAGS}
--- icu/source/config/icu.pc.in	2013-01-11 01:23:56.000000000 +0100
+++ icu/source/config/icu.pc.in	2013-01-24 17:33:21.745635620 +0100
@@ -1,27 +1,27 @@
 # Copyright (C) 2010, International Business Machines Corporation. All Rights Reserved.
 
-prefix = @prefix@
-exec_prefix = @exec_prefix@
-#bindir = @bindir@
-libdir = @libdir@
-includedir = @includedir@
-baselibs = @LIBS@
-#datarootdir = @datarootdir@
-#datadir = @datadir@
-#sbindir = @sbindir@
-#mandir = @mandir@
-#sysconfdir = @sysconfdir@
-CFLAGS = @CFLAGS@ 
-#CXXFLAGS = @CXXFLAGS@ 
-DEFS = @DEFS@ 
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+#bindir=@bindir@
+libdir=@libdir@
+includedir=@includedir@
+baselibs=@LIBS@
+#datarootdir=@datarootdir@
+#datadir=@datadir@
+#sbindir=@sbindir@
+#mandir=@mandir@
+#sysconfdir=@sysconfdir@
+CFLAGS=@CFLAGS@ 
+#CXXFLAGS=@CXXFLAGS@ 
+DEFS=@DEFS@ 
 UNICODE_VERSION=@UNICODE_VERSION@
 ICUPREFIX=icu
 ICULIBSUFFIX=@ICULIBSUFFIX@
-LIBICU=lib${ICUPREFIX}
+LIBICU=${ICUPREFIX}
 #SHAREDLIBCFLAGS=-fPIC
 pkglibdir=${libdir}/@PACKAGE@${ICULIBSUFFIX}/@VERSION@
 #pkgdatadir=${datadir}/@PACKAGE@${ICULIBSUFFIX}/@VERSION@
-ICUDATA_NAME = icudt@LIB_VERSION_MAJOR@@ICUDATA_CHAR@
+ICUDATA_NAME=icudata@LIB_VERSION_MAJOR@@ICUDATA_CHAR@
 #ICUPKGDATA_DIR=@libdir@
 #ICUDATA_DIR=${pkgdatadir}
 ICUDESC=International Components for Unicode
--- icu/source/config/Makefile.inc.in	2013-01-11 01:23:56.000000000 +0100
+++ icu/source/config/Makefile.inc.in	2013-01-24 18:07:14.400256655 +0100
@@ -41,7 +41,7 @@
 # The prefix for ICU libraries, normally 'icu'
 ICUPREFIX = icu
 PACKAGE = @PACKAGE@
-LIBICU = lib$(ICUPREFIX)
+LIBICU = $(ICUPREFIX)
 
 # Static library prefix and file extension
 STATIC_PREFIX = s
@@ -106,18 +106,19 @@
 #    - $(ICULIBS_LAYOUT)  - ICU layout library. 
 #    - $(ICULIBS_ICUIO)   - ICU stdio equivalent library
 
-ICULIBS_COMMON = -l$(ICUPREFIX)uc$(ICULIBSUFFIX)$(ICULIBSUFFIX_VERSION)
-ICULIBS_DATA   = -l$(ICUPREFIX)$(DATA_STUBNAME)$(ICULIBSUFFIX)$(ICULIBSUFFIX_VERSION)
-ICULIBS_I18N   = -l$(ICUPREFIX)$(I18N_STUBNAME)$(ICULIBSUFFIX)$(ICULIBSUFFIX_VERSION)
-ICULIBS_TOOLUTIL = -l$(ICUPREFIX)tu$(ICULIBSUFFIX)$(ICULIBSUFFIX_VERSION)
-ICULIBS_CTESTFW = -l$(ICUPREFIX)ctestfw$(ICULIBSUFFIX)$(ICULIBSUFFIX_VERSION)
-ICULIBS_ICUIO = -l$(ICUPREFIX)io$(ICULIBSUFFIX)$(ICULIBSUFFIX_VERSION)
-ICULIBS_OBSOLETE = -l$(ICUPREFIX)obsolete$(ICULIBSUFFIX)$(ICULIBSUFFIX_VERSION)
-ICULIBS_LAYOUT = -l$(ICUPREFIX)le$(ICULIBSUFFIX)$(ICULIBSUFFIX_VERSION)
-ICULIBS_LAYOUTEX = -l$(ICUPREFIX)lx$(ICULIBSUFFIX)$(ICULIBSUFFIX_VERSION)
+ICULIBS_COMMON = -l$(ICUPREFIX)uc$(ICULIBSUFFIX)
+ICULIBS_DATA   = -l$(ICUPREFIX)$(DATA_STUBNAME)$(ICULIBSUFFIX)
+ICULIBS_I18N   = -l$(ICUPREFIX)$(I18N_STUBNAME)$(ICULIBSUFFIX)
+ICULIBS_TOOLUTIL = -l$(ICUPREFIX)tu$(ICULIBSUFFIX)
+ICULIBS_CTESTFW = -l$(ICUPREFIX)ctestfw$(ICULIBSUFFIX)
+ICULIBS_ICUIO = -l$(ICUPREFIX)io$(ICULIBSUFFIX)
+ICULIBS_OBSOLETE = -l$(ICUPREFIX)obsolete$(ICULIBSUFFIX)
+ICULIBS_LAYOUT = -l$(ICUPREFIX)le$(ICULIBSUFFIX)
+ICULIBS_LAYOUTEX = -l$(ICUPREFIX)lx$(ICULIBSUFFIX)
 ICULIBS_BASE = $(LIBS) -L$(libdir)
 
 # for icu-config to test with
+SO = dll
 ICULIBS_COMMON_LIB_NAME = ${LIBICU}${COMMON_STUBNAME}${ICULIBSUFFIX}${ICULIBSUFFIX_VERSION}.${SO}
 ICULIBS_COMMON_LIB_NAME_A = ${LIBICU}${COMMON_STUBNAME}${ICULIBSUFFIX}.${A}
 
--- icu/source/config/mh-mingw	2013-01-11 01:23:56.000000000 +0100
+++ icu/source/config/mh-mingw	2013-01-24 18:42:02.996026071 +0100
@@ -41,8 +41,8 @@
 LD_SOOPTIONS= -Wl,-Bsymbolic
 
 ## Commands to make a shared library
-SHLIB.c=	$(CC) $(CFLAGS) $(LDFLAGS) -shared $(LD_SOOPTIONS) -Wl,--enable-auto-import -Wl,--out-implib=$(dir $@)$(notdir $(@:$(SO_TARGET_VERSION_MAJOR).$(SO)=))$(IMPORT_LIB_EXT)#M#
-SHLIB.cc=	$(CXX) $(CXXFLAGS) $(LDFLAGS) -shared $(LD_SOOPTIONS) -Wl,--enable-auto-import -Wl,--out-implib=$(dir $@)$(notdir $(@:$(SO_TARGET_VERSION_MAJOR).$(SO)=))$(IMPORT_LIB_EXT)#M#
+SHLIB.c=	$(CC) $(CFLAGS) $(LDFLAGS) -shared $(LD_SOOPTIONS) -Wl,--enable-auto-import -Wl,--out-implib=$(dir $@)$(LIBPREFIX)$(notdir $(@:$(SO_TARGET_VERSION_MAJOR).$(SO)=))$(IMPORT_LIB_EXT)#M#
+SHLIB.cc=	$(CXX) $(CXXFLAGS) $(LDFLAGS) -shared $(LD_SOOPTIONS) -Wl,--enable-auto-import -Wl,--out-implib=$(dir $@)$(LIBPREFIX)$(notdir $(@:$(SO_TARGET_VERSION_MAJOR).$(SO)=))$(IMPORT_LIB_EXT)#M#
 
 ## Compiler switch to embed a runtime search path
 LD_RPATH=	
@@ -63,19 +63,15 @@
 endif
 
 # Static library prefix and file extension
-LIBSICU = $(LIBPREFIX)$(STATIC_PREFIX)$(ICUPREFIX)
+LIBSICU = $(LIBPREFIX)$(ICUPREFIX)
 A = a
 
 ## An import library is needed for z/OS and MSVC
-IMPORT_LIB_EXT = .lib
+IMPORT_LIB_EXT = .dll.a
 
 LIBPREFIX=
 
-# Change the stubnames so that poorly working FAT disks and installation programs can work.
-# This is also for backwards compatibility.
-DATA_STUBNAME = dt
-I18N_STUBNAME = in
-LIBICU = $(STATIC_PREFIX_WHEN_USED)$(ICUPREFIX)
+LIBICU = $(ICUPREFIX)
 
 # The #M# is used to delete lines for icu-config
 # Current full path directory.
@@ -115,7 +111,7 @@
 FINAL_SO_TARGET=$(basename $(SO_TARGET))$(SO_TARGET_VERSION_MAJOR).$(SO)
 MIDDLE_SO_TARGET=$(FINAL_SO_TARGET)
 
-FINAL_IMPORT_LIB = $(dir $(SO_TARGET))$(notdir $(basename $(SO_TARGET)))$(IMPORT_LIB_EXT)#M#
+FINAL_IMPORT_LIB = $(dir $(SO_TARGET))$(LIBPREFIX)$(notdir $(basename $(SO_TARGET)))$(IMPORT_LIB_EXT)#M#
 IMPORT_LIB = $(FINAL_IMPORT_LIB)#M#
 MIDDLE_IMPORT_LIB = $(FINAL_IMPORT_LIB)#M#
 
@@ -124,6 +120,9 @@
 #ICUPKGDATA_INSTALL_DIR = $(shell cygpath -dma $(DESTDIR)$(ICUPKGDATA_DIR))#M#
 #ICUPKGDATA_INSTALL_LIBDIR = $(shell cygpath -dma $(DESTDIR)$(libdir))#M#
 
+# The following is for Makefile.inc's use.
+ICULIBSUFFIX_VERSION = $(LIB_VERSION_MAJOR)
+
 ## Versioned libraries rules
 #%$(SO_TARGET_VERSION_MAJOR).$(SO): %$(SO_TARGET_VERSION).$(SO)
 #	$(RM) $@ && cp ${<F} $@
@@ -139,5 +138,17 @@
 # These are needed to allow the pkgdata GNU make files to work
 PKGDATA_DEFS = -DU_MAKE=\"$(MAKE)\"
 
+# Just the libs.
+ICULIBS_DT	= -l$(STATIC_PREFIX_WHEN_USED)$(ICUPREFIX)$(DATA_STUBNAME)$(ICULIBSUFFIX)
+ICULIBS_UC	= -l$(STATIC_PREFIX_WHEN_USED)$(ICUPREFIX)$(COMMON_STUBNAME)$(ICULIBSUFFIX)
+ICULIBS_I18N	= -l$(STATIC_PREFIX_WHEN_USED)$(ICUPREFIX)$(I18N_STUBNAME)$(ICULIBSUFFIX)
+ICULIBS_LE	= -l$(STATIC_PREFIX_WHEN_USED)$(ICUPREFIX)$(LAYOUT_STUBNAME)$(ICULIBSUFFIX)
+ICULIBS_LX	= -l$(STATIC_PREFIX_WHEN_USED)$(ICUPREFIX)$(LAYOUTEX_STUBNAME)$(ICULIBSUFFIX)
+ICULIBS_IO	= -l$(STATIC_PREFIX_WHEN_USED)$(ICUPREFIX)$(IO_STUBNAME)$(ICULIBSUFFIX)
+ICULIBS_CTESTFW	= -l$(STATIC_PREFIX_WHEN_USED)$(ICUPREFIX)$(CTESTFW_STUBNAME)$(ICULIBSUFFIX)
+ICULIBS_TOOLUTIL = -l$(STATIC_PREFIX_WHEN_USED)$(ICUPREFIX)$(TOOLUTIL_STUBNAME)$(ICULIBSUFFIX)
+# Link commands to link to ICU libs
+LLIBDIR		= -L$(LIBDIR)
+
 ## End Cygwin/MinGW specific setup
 
--- icu/source/tools/toolutil/pkg_genc.c	2013-01-11 01:23:40.000000000 +0100
+++ icu/source/tools/toolutil/pkg_genc.c	2013-01-24 17:32:54.453298904 +0100
@@ -150,6 +150,22 @@
 
         ".long ","",HEX_0X
     },
+    {"gcc-mingw-x86",
+        ".globl _%s\n"
+        "\t.section .rdata,\"dr\"\n"
+        "\t.align 4\n"
+        "_%s:\n\n",
+
+        ".long ","",HEX_0X
+    },
+    {"gcc-mingw-x64",
+        ".globl %s\n"
+        "\t.section .rdata,\"dr\"\n"
+        "\t.align 16\n" /* Either align 8 bytes or 2^8 (256) bytes. 8 bytes is needed. */
+        "%s:\n\n",
+
+        ".long ","",HEX_0X
+    },
     {"sun",
         "\t.section \".rodata\"\n"
         "\t.align   8\n"