./configure run on Windows

gistfile1.txt

Setting environment for using Microsoft Visual Studio 2010 x86 tools.

C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC>cd C:\Users\Nathan\Documents\node-ffi\deps\libffi

C:\Users\Nathan\Documents\node-ffi\deps\libffi>sh configure CC="sh C:\Users\Nathan\Documents\node-ffi\deps\libffi\msvcc.
sh" LD=link CPP="cl -nologo -EP"
checking build system type... i686-pc-mingw32
checking host system type... i686-pc-mingw32
checking target system type... i686-pc-mingw32
continue configure in default builddir "./i686-pc-mingw32"
....exec /bin/sh ../configure "--srcdir=.." "--enable-builddir=i686-pc-mingw32" "mingw32"
checking build system type... i686-pc-mingw32
checking host system type... i686-pc-mingw32
checking target system type... i686-pc-mingw32
checking for gsed... sed
checking for a BSD-compatible install... ../install-sh -c
checking whether build environment is sane... yes
checking for a thread-safe mkdir -p... /usr/bin/mkdir -p
checking for gawk... gawk
checking whether make sets $(MAKE)... no
checking for gcc... sh C:\Users\Nathan\Documents\node-ffi\deps\libffi\msvcc.sh
checking whether the C compiler works... yes
checking for C compiler default output file name... conftest.exe
checking for suffix of executables... .exe
checking whether we are cross compiling... no
checking for suffix of object files... obj
checking whether we are using the GNU C compiler... no
checking whether sh C:\Users\Nathan\Documents\node-ffi\deps\libffi\msvcc.sh accepts -g... yes
checking for sh C:\Users\Nathan\Documents\node-ffi\deps\libffi\msvcc.sh option to accept ISO C89... none needed
checking for style of include used by make... none
checking dependency style of sh C:\Users\Nathan\Documents\node-ffi\deps\libffi\msvcc.sh... none
checking dependency style of sh C:\Users\Nathan\Documents\node-ffi\deps\libffi\msvcc.sh... none
checking whether sh C:\Users\Nathan\Documents\node-ffi\deps\libffi\msvcc.sh and cc understand -c and -o together... yes
checking how to print strings... printf
checking for a sed that does not truncate output... /usr/bin/sed
checking for grep that handles long lines and -e... /usr/bin/grep
checking for egrep... /usr/bin/grep -E
checking for fgrep... /usr/bin/grep -F
checking for non-GNU ld... link
checking if the linker (link) is GNU ld... no
checking for BSD- or MS-compatible name lister (nm)... no
checking for dumpbin... dumpbin
checking the name lister (dumpbin -symbols) interface... MS dumpbin
checking whether ln -s works... no, using cp -p
checking the maximum length of command line arguments... 8192
checking whether the shell understands some XSI constructs... yes
checking whether the shell understands "+="... yes
checking how to convert i686-pc-mingw32 file names to i686-pc-mingw32 format... func_convert_file_msys_to_w32
checking how to convert i686-pc-mingw32 file names to toolchain format... func_convert_file_msys_to_w32
checking for link option to reload object files... -r
checking for objdump... no
checking how to recognize dependent libraries... file_magic file format (pei*-i386(.*architecture: i386)?|pe-arm-wince|p
e-x86-64)
checking for dlltool... no
checking how to associate runtime and link libraries... func_cygming_dll_for_implib_fallback
checking for ar... no
checking for archiver @FILE support... no
checking for strip... no
checking for ranlib... no
checking command to parse dumpbin -symbols output from sh C:\Users\Nathan\Documents\node-ffi\deps\libffi\msvcc.sh object
... ok
checking for sysroot... no
checking for mt... mt
checking if mt is a manifest tool... yes
checking how to run the C preprocessor... cl -nologo -EP
checking for ANSI C header files... yes
checking for sys/types.h... yes
checking for sys/stat.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for memory.h... yes
checking for strings.h... no
checking for inttypes.h... no
checking for stdint.h... yes
checking for unistd.h... no
checking for dlfcn.h... no
checking for objdir... .libs
checking for sh C:\Users\Nathan\Documents\node-ffi\deps\libffi\msvcc.sh option to produce PIC... -DDLL_EXPORT -DPIC
checking if sh C:\Users\Nathan\Documents\node-ffi\deps\libffi\msvcc.sh PIC flag -DDLL_EXPORT -DPIC works... yes
checking if sh C:\Users\Nathan\Documents\node-ffi\deps\libffi\msvcc.sh static flag  works... yes
checking if sh C:\Users\Nathan\Documents\node-ffi\deps\libffi\msvcc.sh supports -c -o file.obj... yes
checking if sh C:\Users\Nathan\Documents\node-ffi\deps\libffi\msvcc.sh supports -c -o file.obj... (cached) yes
checking whether the sh C:\Users\Nathan\Documents\node-ffi\deps\libffi\msvcc.sh linker (link) supports shared libraries.
.. yes
checking dynamic linker characteristics... Win32 ld.exe
checking how to hardcode library paths into programs... immediate
checking whether stripping libraries is possible... no
checking if libtool supports shared libraries... yes
checking whether to build shared libraries... yes
checking whether to build static libraries... yes
checking for C compiler vendor... microsoft

********************************************************
* WARNING: Don't know the best CFLAGS for this system  *
* Use ./configure CFLAGS=... to specify your own flags *
* (otherwise, a default of CFLAGS=-O3 will be used)    *
********************************************************

checking whether C compiler accepts -O3... yes
checking CFLAGS for maximum warnings... -Wall
checking whether to enable maintainer-specific portions of Makefiles... no
checking sys/mman.h usability... no
checking sys/mman.h presence... no
checking for sys/mman.h... no
checking for mmap... no
checking for sys/mman.h... (cached) no
checking for mmap... (cached) no
checking for ANSI C header files... (cached) yes
checking for memcpy... yes
checking for size_t... yes
checking for working alloca.h... no
checking for alloca... yes
checking size of double... 8
checking size of long double... 8
checking whether byte ordering is bigendian... no
checking assembler .cfi pseudo-op support... no
checking assembler supports pc related relocs... cl : Command line warning D9002 : ignoring unknown option '-O3'
cl : Command line warning D9002 : ignoring unknown option '-OP'
cl : Command line warning D9002 : ignoring unknown option '-OT'
cl : Command line warning D9002 : ignoring unknown option '-O:'
cl : Command line warning D9002 : ignoring unknown option '-OR'
cl : Command line warning D9002 : ignoring unknown option '-OE'
cl : Command line warning D9002 : ignoring unknown option '-OF'
cl : Command line warning D9002 : ignoring unknown option '-OP'
cl : Command line warning D9002 : ignoring unknown option '-OT'
cl : Command line warning D9002 : ignoring unknown option '-O:'
cl : Command line warning D9002 : ignoring unknown option '-OI'
cl : Command line warning D9002 : ignoring unknown option '-OC'
cl : Command line warning D9002 : ignoring unknown option '-OF'
cl : Command line warning D9024 : unrecognized source file type 'conftest.s', object file assumed
cl : Command line warning D9027 : source file 'conftest.s' ignored
yes
checking assembler .ascii pseudo-op support... no
checking assembler .string pseudo-op support... no
cl : Command line warning D9002 : ignoring unknown option '-print-multi-os-directory'
cl : Command line error D8003 : missing source filename
configure: creating ./config.status
config.status: creating include/Makefile
config.status: creating include/ffi.h
config.status: creating Makefile
config.status: creating testsuite/Makefile
config.status: creating man/Makefile
config.status: creating libffi.pc
config.status: creating fficonfig.h
config.status: linking ../src/x86/ffitarget.h to include/ffitarget.h
config.status: executing buildir commands
config.status: create top_srcdir/Makefile guessed from local Makefile
config.status: build in i686-pc-mingw32 (HOST=)
config.status: executing depfiles commands
config.status: executing libtool commands
config.status: executing include commands
config.status: executing src commands

C:\Users\Nathan\Documents\node-ffi\deps\libffi>

It looks as if msvcc.sh isn't handling -O options at all, and improperly handling assembly files. You might also provide a blank CFLAGS (see the warning). BTW, msvcc.sh was originally derived from cc.sh/ld.sh in JNA (https://github.com/twall/jna/tree/master/native). JNA properly runs configure/build under gcc/cygwin and mingw/msys to build libffi for later use.