+#-----------------------------------------------------------------------------#
+
+# Makefile.DLLs, version 0.7.
+
+# This Makefile contains rules for creating DLLs on Windows using gnu-win32.
+
+#-----------------------------------------------------------------------------#
+
+# The SYM_PREFIX is used as a prefix for the symbols in the files
+# that this makefiles automatically generates.
+#
+# The default SYM_PREFIX for libfoo.dll is `libfoo'.
+# But you can override this by setting `SYM_PREFIX-libfoo = blah'.
+
+SYM_PREFIX = $(firstword $(SYM_PREFIX-$*) $*)
+
+GUARD_MACRO = $(SYM_PREFIX)_GLOBALS_H
+DEFINE_DLL_MACRO = $(SYM_PREFIX)_DEFINE_DLL
+USE_DLL_MACRO = $(SYM_PREFIX)_USE_DLL
+IMP_MACRO = $(SYM_PREFIX)_IMP
+GLOBAL_MACRO = $(SYM_PREFIX)_GLOBAL
+IMPURE_PTR = $(SYM_PREFIX)_impure_ptr
+
+# This rule creates a `.def' file, which lists the symbols that are exported
+# from the DLL. We use `nm' to get a list of all the exported text (`T')
+# symbols and data symbols -- including uninitialized data (`B'),
+# initialized data (`D'), read-only data (`R'), and common blocks (`C').
+# We also export `_impure_ptr', suitably renamed, so that the
+# main program can do the necessary initialization of the DLL's _impure_ptr.
+# (Since there can be more than one DLL, we must rename _impure_ptr as
+# $(SYM_PREFIX)_impure_ptr to prevent name collisions.)
+#%.def: %.a
+# echo EXPORTS > $@
+# echo $(IMPURE_PTR) = _impure_ptr >> $@
+# nm $< | sed -n '/^........ [BCDRT] _/s/[^_]*_//p' >> $@
+
+# We need to use macros to access global data:
+# the user of the DLL must refer to `bar' as `(*__imp_bar)'.
+# This rule creates a pair of files `foo_dll.h' and `foo_globals.h'
+# which contains macros for doing this.
+#
+# The DLL may also contain some references to _impure_ptr
+# (e.g. stdin is defined as a macro which expands to _impure_ptr.stdin).
+# We need to provide a definition for this (otherwise it will link in
+# the definition in libccrt.o, which causes lots of problems,
+# eventually leading to undefined symbol `WinMain').
+# The DLL's entry function (below) will initialize the _impure_ptr variable
+# in the DLL so that they point to the main program's reent_data struct.
+
+%_dll.h:
+ echo "/* automatically generated by Makefile.DLLs */" > $@
+ echo "#ifndef $(GUARD_MACRO)" >> $@
+ echo "#define $(GUARD_MACRO)" >> $@
+ echo "" >> $@
+ echo "#if defined(__GNUC__) && defined(__CYGWIN32__)" >> $@
+ echo " #if defined($(USE_DLL_MACRO))" >> $@
+ echo " #define $(IMP_MACRO)(name) __imp_##name" >> $@
+ echo " #define $(GLOBAL_MACRO)(name) (*$(IMP_MACRO)(name))" >> $@
+ echo " #include \"$*_globals.h\"" >> $@
+ echo " #endif /* $(USE_DLL_MACRO) */" >> $@
+ echo "#endif /* __GNUC__ && __CYGWIN32__ */" >> $@
+ echo "" >> $@
+ echo "#endif /* $(GUARD_MACRO) */" >> $@
+
+%_globals.h: %.a
+ echo "/* automatically generated by Makefile.DLLs */" > $@
+ for sym in $(IMPURE_PTR) \
+ `nm $< | grep '^........ [BCDR] _' | sed 's/[^_]*_//'`; \
+ do \
+ echo "#define $$sym $(GLOBAL_MACRO)($$sym)" >> $@; \
+ done
+
+%_dll.c:
+ echo "/* automatically generated by Makefile.DLLs */" > $@
+ echo "void *_impure_ptr;" >> $@
+
+# This rule creates the export object file (`foo.exp') which contains the
+# jump table array; this export object file becomes part of the DLL.
+# This rule also creates the import library (`foo_dll.a') which contains small
+# stubs for all the functions exported by the DLL which jump to them via the
+# jump table. Executables that will use the DLL must be linked against this
+# stub library.
+%.exp %_dll.a : %.def
+ dlltool $(DLLTOOLFLAGS) $(DLLTOOLFLAGS-$*) \
+ --def $< \
+ --dllname $*.dll \
+ --output-exp $*.exp \
+ --output-lib $*_dll.a
+
+# The `sed' commands below are to convert DOS-style `C:\foo\bar'
+# pathnames into Unix-style `//c/foo/bar' pathnames.
+CYGWIN32_LIBS = $(shell echo \
+ -L`dirname \`gcc -print-file-name=libgcc.a | \
+ sed -e 's@^\\\\([A-Za-z]\\\\):@//\\\\1@g' -e 's@\\\\\\\\@/@g' \` ` \
+ -L`dirname \`gcc -print-file-name=libcygwin.a | \
+ sed -e 's@^\\\\([A-Za-z]\\\\):@//\\\\1@g' -e 's@\\\\\\\\@/@g' \` ` \
+ -L`dirname \`gcc -print-file-name=libkernel32.a | \
+ sed -e 's@^\\\\([A-Za-z]\\\\):@//\\\\1@g' -e 's@\\\\\\\\@/@g' \` ` \
+ -lgcc -lcygwin -lkernel32 -lgcc)
+
+# Making relocatable DLLs doesn't seem to work.
+# Not quite sure why. The --image-base values below
+# where chosen at random, they seem to work on my machine.
+RELOCATABLE=no
+LDFLAGS-libgc += --image-base=0x2345000
+LDFLAGS-libmer += --image-base=0x1234000
+LDFLAGS-libmercury += --image-base=0x3456000
+
+ifeq "$(strip $(RELOCATABLE))" "yes"
+
+# to create relocatable DLLs, we need to do two passes
+# (warning: this is untested)
+%.dll: %.exp %.a %_dll.o dll_init.o dll_fixup.o
+ $(LD) $(LDFLAGS) $(LDFLAGS-$*) --dll -o $*.base \
+ -e _dll_entry@12 \
+ $*.exp $*.a $*_dll.o \
+ dll_init.o dll_fixup.o \
+ $(LDLIBS) $(LDLIBS-$*) \
+ $(CYGWIN32_LIBS)
+ # untested
+ dlltool $(DLLTOOLFLAGS) $(DLLTOOLFLAGS-$*) \
+ --def $*.def \
+ --dllname $*.dll \
+ --base-file $*.base \
+ --output-exp $*.exp
+ $(LD) $(LDFLAGS) $(LDFLAGS-$*) --dll -o $*.base \
+ -e _dll_entry@12 \
+ $*.exp $*.a $*_dll.o \
+ dll_init.o dll_fixup.o \
+ $(LDLIBS) $(LDLIBS-$*) \
+ $(CYGWIN32_LIBS)
+ dlltool $(DLLTOOLFLAGS) $(DLLTOOLFLAGS-$*) \
+ --def $*.def \
+ --dllname $*.dll \
+ --base-file $*.base \
+ --output-exp $*.exp
+ # end untested stuff
+ $(LD) $(LDFLAGS) $(LDFLAGS-$*) --dll --base-file $*.base -o $@ \
+ -e _dll_entry@12 \
+ $*.exp $*.a $*_dll.o \
+ dll_init.o dll_fixup.o \
+ $(LDLIBS) $(LDLIBS-$*) \
+ $(CYGWIN32_LIBS)
+ rm -f $*.base
+
+else
+
+%.dll: %.exp %.a %_dll.o dll_fixup.o dll_init.o
+ $(LD) $(LDFLAGS) $(LDFLAGS-$*) --dll -o $@ \
+ -e _dll_entry@12 \
+ $*.exp $*.a $*_dll.o \
+ dll_init.o dll_fixup.o \
+ $(LDLIBS) $(LDLIBS-$*) \
+ $(CYGWIN32_LIBS)
+
+endif
+
+# This black magic piece of assembler needs to be linked in in order to
+# properly terminate the list of imported DLLs.
+dll_fixup.s:
+ echo '.section .idata$$3' > dll_fixup.s
+ echo '.long 0,0,0,0,0' >> dll_fixup.s
+
+dll_fixup.o: dll_fixup.s
+ $(AS) $(ASFLAGS) -o dll_fixup.o dll_fixup.s
+
+# Windows requires each DLL to have an initialization function
+# that is called at certain points (thread/process attach/detach).
+# This one just initializes `_impure_ptr'.
+dll_init.c:
+ echo '#include <stdio.h>' > dll_init.c
+ echo 'extern struct _reent *_impure_ptr;' >> dll_init.c
+ echo 'extern struct _reent *__imp_reent_data;' >> dll_init.c
+ echo '__attribute__((stdcall))' >> dll_init.c
+ echo 'int dll_entry(int handle, int reason, void *ptr)' >> dll_init.c
+ echo '{ _impure_ptr=__imp_reent_data; return 1; }' >> dll_init.c
+
+# The following rule is just there to convince gcc
+# to keep otherwise unused intermediate targets around.
+dont_throw_away: dll_fixup.o dll_init.o