Makefile.embedded - hybrid DynCall makefiles for GNU, BSD and SUN make
======================================================================


Brief overview
--------------
This is one of the latest build systems designed for DynCall.
It was designed for being embeddable in bigger 'make' based systems.
It uses a very simple structure and it does not require any 'configure' phase.
Instead the user can specify the CFLAGS and LDFLAGS by himself.
For a couple of platforms, the make system supports phony targets of popular
operating-systems such as 'bsd'.

Building the library:
---------------------
$ make -f Makefile.embedded <variant>

Building the tests:
-------------------
$ cd test ; make -f Makefile.embedded <variant>

Installation:
-------------
$ make -f Makefile.embedded PREFIX=/usr/local install

Installation with support for DESTDIR:
--------------------------------------
$ make -f Makefile.embedded DESTDIR=/tmp/staging PREFIX=/usr/local install


Available variants:
-------------------
bsd                   Free/Net/Open/DragonFly/Mir BSD     
linux                 Linux
osx                   Mac OS X
osx-universal         Mac OS X universal binaries (i386,x86_64 and ppc)
sun                   SunOS and Sun Pro compiler
sun-64bit             SunOS and Sun Pro compiler for sparc64(? amd64) 
sun-gcc               SunOS and GCC compiler
sun-gcc-64bit         SunOS and GCC compiler for sparc64 (? amd64)
ios61                 iOS SDK 6.1 armv7  (untested!)
ios61-nothumb         iOS SDK 6.1 armv7 -mno-thumb (untested!)

Tweaking the build:
-------------------
$ VAR1=<VALUE1> VAR2=<VALUE2> .. make -f Makefile.embedded <variant>

Adding a variant
-----------------
Currently we deal with two files to specify a custom target.

The top-level Makefile.embedded controls for building the libraries.
Useful variables are AR, CC, CFLAGS and ASFLAGS.

The test/Makefile.embedded file controls for building the tests.
The tests currently involve sometimes C++ and some platforms need
to link with the math library. Others need the dynamic linker.
Useful variables are CXX, CC, CCC (Sun), CFLAGS, CCFLAGS (Sun), 
CXXFLAGS andLDFLAGS.

Background
----------
During the preparation for the public release of the R package 'rdyncall' I was 
looking for a way to get DynCall integrated into an existing Make system such 
as offered by R for build R packages. 

It was inspired by the make files of Lua which are damn simple and
don't need a configure but a user that knows the target platform name.

The source package can be configured automatically during compilation and
does not require explicit configuration anymore using "*.S" files that
are Assembly files which are preprocessed by the C Preprocessor.

This feature is available by GCC and SunPro compilers.

Limitations
-----------

Mac OS X universal static libraries require to use 

'libtool -static -o libname.a obj1.o obj2.o ...' instead of 'ar cru libname.a obj1.o obj2.o'.
We use predefined variables AR and ARFLAGS. 
The variant osx-universal uses AR=libtool.