* Remove old non-maintained mingw makefile to prevent confusion

* Add notes on building with MinGW to Build.md

Build.md

@@ -23,7 +23,7 @@ This will generate the project files for the visual studio. All dependencies use
 See https://stackoverflow.com/questions/40803170/cmake-uwp-using-cmake-to-build-universal-windows-app
 
 
-# Build instrcutions for Linux / Unix
+# Build instructions for Linux / Unix
 Open a terminal and got to your repository. You can generate the makefiles and build the library via:
 
 ```
@@ -34,6 +34,17 @@ The option -j descripes the number of parallel processes for the build. In this
 
 If you want to use a IDE for linux you can try QTCreator for instance. 
 
+# Build instructions for MinGW
+
+Please see [CMake Cross Compiling](https://cmake.org/cmake/help/latest/manual/cmake-toolchains.7.html#cross-compiling) for general information on CMake Toolchains.
+
+Some users have had success building assimp using MinGW on Linux using the following toolchain, which is not maintained by assimp. [linux-mingw-w64-gnuxx11.cmake](https://github.com/ruslo/polly/blob/master/linux-mingw-w64-gnuxx11.cmake)
+
+The following toolchain may or may not be helpful for building assimp using MinGW on Windows (untested):
+ [mingw-cxx17.cmake](https://github.com/ruslo/polly/blob/master/mingw-cxx17.cmake)
+
+Besides the toolchain, compilation should be the same as for Linux / Unix
+
 # CMake build options
 The cmake-build-environment provides options to configure the build. The following options can be used:
 - **BUILD_SHARED_LIBS ( default ON )**: Generation of shared libs ( dll for windows, so for Linux ). Set this to OFF to get a static lib.

code/makefile.mingw

@@ -1,105 +0,0 @@
-### USE OF THIS MAKEFILE IS NOT RECOMMENDED.
-### It is no longer maintained. Use CMAKE instead.
-
-# ---------------------------------------------------------------------------
-# Makefile for Open Asset Import Library (MinGW32-make)
-# [email protected]
-#   - just a quick'n'dirty one, could be buggy ...
-#
-# Usage: mingw32-make -f makefile.mingw <target> <macros>
-
-# TARGETS:
-#   all                  Build a shared so from the whole library
-#   clean                Cleanup object files, prepare for rebuild
-#   static               Build a static library (*.a)
-
-# MACROS: (make clean before you change one)
-#   NOBOOST=1            Build against boost workaround
-#   SINGLETHREADED=1     Build single-threaded library
-#   DEBUG=1              Build debug build of library
-# 
-# ---------------------------------------------------------------------------
-
-# C++ object files
-OBJECTS   := $(patsubst %.cpp,%.o,  $(wildcard *.cpp)) 
-OBJECTS   += $(patsubst %.cpp,%.o,  $(wildcard extra/*.cpp)) 
-OBJECTS   += $(patsubst %.cpp,%.o,  $(wildcard ./../contrib/irrXML/*.cpp)) 
-
-# C object files 
-OBJECTSC  := $(patsubst %.c,%.oc,   $(wildcard ./../contrib/zlib/*.c))
-OBJECTSC  += $(patsubst %.c,%.oc,   $(wildcard ./../contrib/ConvertUTF/*.c))
-OBJECTSC  += $(patsubst %.c,%.oc,   $(wildcard ./../contrib/unzip/*.c))
-
-# Include flags for gcc
-INCLUDEFLAGS =
-
-# Preprocessor defines for gcc
-DEFINEFLAGS = 
-
-# Suffix for the output binary, represents build type
-NAMESUFFIX = 
-
-# Output path for binaries
-BINPATH = ../bin/mingw/
-
-# GCC compiler flags 
-CPPFLAGS=-Wall 
-
-# Setup environment for noboost build
-ifeq ($(NOBOOST),1)
-	SINGLETHREADED = 1
-	INCLUDEFLAGS  += -I./BoostWorkaround/
-	DEFINEFLAGS   += -DASSIMP_BUILD_BOOST_WORKAROUND 
-#	NAMESUFFIX    += -noboost
-else
-	# adjust this manually if your boost is stored elsewhere
-	INCLUDEFLAGS  += -I"C:/Program Files/boost/boost_1_38"
-	#INCLUDEFLAGS  += -I"$(BOOST_DIR)"
-
-endif
-
-# Setup environment for st build
-ifeq ($(SINGLETHREADED),1)
-	DEFINEFLAGS   += -DASSIMP_BUILD_SINGLETHREADED
-#	NAMESUFFIX    += -st
-endif
-
-# Setup environment for debug build
-ifeq ($(DEBUG),1)
-	DEFINEFLAGS   += -D_DEBUG -DDEBUG
-	CPPFLAGS      += -g
-#	NAMESUFFIX    += -debug
-else
-	CPPFLAGS      += -O2 -s
-	DEFINEFLAGS   += -DNDEBUG -D_NDEBUG
-endif
-
-# Output name of shared library
-SHARED_TARGET = $(BINPATH)/libassimp$(NAMESUFFIX).so
-
-# Output name of static library
-STATIC = $(BINPATH)/libassimp$(NAMESUFFIX).a
-
-# target: all
-# usage : build a shared library (*.so)
-all:	$(SHARED_TARGET)
-
-$(SHARED_TARGET):  $(OBJECTS)  $(OBJECTSC)
-	gcc -o $@ $(OBJECTS) $(OBJECTSC) -shared -lstdc++ 
-%.o:%.cpp
-	$(CXX) -c  $(CPPFLAGS) $? -o $@ $(INCLUDEFLAGS) $(DEFINEFLAGS)
-%.oc:%.c
-	$(CXX) -x c -c -ansi $(CPPFLAGS) $? -o $@ 
-
-# target: clean
-# usage : cleanup all object files, prepare for a rebuild
-.PHONY: clean
-clean:
-	-del *.o .\..\contrib\irrXML\*.o .\..\contrib\zlib\*.oc .\..\contrib\unzip\*.oc .\..\contrib\ConvertUTF\*.oc
-
-# target: static
-# usage : build a static library (*.a)
-static:    $(STATIC) 
-$(STATIC):    $(OBJECTS) $(OBJECTSC)
-	ar rcs $@ $(OBJECTS) $(OBJECTSC)
-