Fix compilation of NIFs on Windows

Thanks to two users of the ninenines/esdl2 project,
a correct way to build NIFs on Windows has been found.

At the moment we require a specific compiler (MingW's
gcc). Maybe we can change this in the future and allow
Visual Studio and others.

Some small changes have been made to the documentation,
and the meaning of one configuration variable has changed
to not include the extension (which is decided automatically
by Erlang.mk; and configurable separately).

Enjoy!

1 files changed, 36 insertions, 11 deletions

diff --git a/plugins/c_src.mk b/plugins/c_src.mk
index e5d6e51..87fd32f 100644
--- a/plugins/c_src.mk
+++ b/plugins/c_src.mk
@@ -7,12 +7,32 @@
 
 C_SRC_DIR ?= $(CURDIR)/c_src
 C_SRC_ENV ?= $(C_SRC_DIR)/env.mk
-C_SRC_OUTPUT ?= $(CURDIR)/priv/$(PROJECT).so
+C_SRC_OUTPUT ?= $(CURDIR)/priv/$(PROJECT)
 C_SRC_TYPE ?= shared
 
 # System type and C compiler/flags.
 
-ifeq ($(PLATFORM),darwin)
+ifeq ($(PLATFORM),msys2)
+	C_SRC_OUTPUT_EXECUTABLE_EXTENSION ?= .exe
+	C_SRC_OUTPUT_SHARED_EXTENSION ?= .dll
+else
+	C_SRC_OUTPUT_EXECUTABLE_EXTENSION ?=
+	C_SRC_OUTPUT_SHARED_EXTENSION ?= .so
+endif
+
+ifeq ($(C_SRC_TYPE),shared)
+	C_SRC_OUTPUT_FILE = $(C_SRC_OUTPUT)$(C_SRC_OUTPUT_SHARED_EXTENSION)
+else
+	C_SRC_OUTPUT_FILE = $(C_SRC_OUTPUT)$(C_SRC_OUTPUT_EXECUTABLE_EXTENSION)
+endif
+
+ifeq ($(PLATFORM),msys2)
+# We hardcode the compiler used on MSYS2. The default CC=cc does
+# not produce working code. The "gcc" MSYS2 package also doesn't.
+	CC = /mingw64/bin/gcc
+	CFLAGS ?= -O3 -std=c99 -finline-functions -Wall -Wmissing-prototypes
+	CXXFLAGS ?= -O3 -finline-functions -Wall
+else ifeq ($(PLATFORM),darwin)
 	CC ?= cc
 	CFLAGS ?= -O3 -std=c99 -arch x86_64 -finline-functions -Wall -Wmissing-prototypes
 	CXXFLAGS ?= -O3 -arch x86_64 -finline-functions -Wall
@@ -27,10 +47,15 @@ else ifeq ($(PLATFORM),linux)
 	CXXFLAGS ?= -O3 -finline-functions -Wall
 endif
 
-CFLAGS += -fPIC -I $(ERTS_INCLUDE_DIR) -I $(ERL_INTERFACE_INCLUDE_DIR)
-CXXFLAGS += -fPIC -I $(ERTS_INCLUDE_DIR) -I $(ERL_INTERFACE_INCLUDE_DIR)
+ifneq ($(PLATFORM),msys2)
+	CFLAGS += -fPIC
+	CXXFLAGS += -fPIC
+endif
+
+CFLAGS += -I"$(ERTS_INCLUDE_DIR)" -I"$(ERL_INTERFACE_INCLUDE_DIR)"
+CXXFLAGS += -I"$(ERTS_INCLUDE_DIR)" -I"$(ERL_INTERFACE_INCLUDE_DIR)"
 
-LDLIBS += -L $(ERL_INTERFACE_LIB_DIR) -lerl_interface -lei
+LDLIBS += -L"$(ERL_INTERFACE_LIB_DIR)" -lerl_interface -lei
 
 # Verbosity.
 
@@ -67,15 +92,15 @@ OBJECTS = $(addsuffix .o, $(basename $(SOURCES)))
 COMPILE_C = $(c_verbose) $(CC) $(CFLAGS) $(CPPFLAGS) -c
 COMPILE_CPP = $(cpp_verbose) $(CXX) $(CXXFLAGS) $(CPPFLAGS) -c
 
-app:: $(C_SRC_ENV) $(C_SRC_OUTPUT)
+app:: $(C_SRC_ENV) $(C_SRC_OUTPUT_FILE)
 
-test-build:: $(C_SRC_ENV) $(C_SRC_OUTPUT)
+test-build:: $(C_SRC_ENV) $(C_SRC_OUTPUT_FILE)
 
-$(C_SRC_OUTPUT): $(OBJECTS)
+$(C_SRC_OUTPUT_FILE): $(OBJECTS)
 	$(verbose) mkdir -p priv/
 	$(link_verbose) $(CC) $(OBJECTS) \
 		$(LDFLAGS) $(if $(filter $(C_SRC_TYPE),shared),-shared) $(LDLIBS) \
-		-o $(C_SRC_OUTPUT)
+		-o $(C_SRC_OUTPUT_FILE)
 
 %.o: %.c
 	$(COMPILE_C) $(OUTPUT_OPTION) $<
@@ -92,13 +117,13 @@ $(C_SRC_OUTPUT): $(OBJECTS)
 clean:: clean-c_src
 
 clean-c_src:
-	$(gen_verbose) rm -f $(C_SRC_OUTPUT) $(OBJECTS)
+	$(gen_verbose) rm -f $(C_SRC_OUTPUT_FILE) $(OBJECTS)
 
 endif
 
 ifneq ($(wildcard $(C_SRC_DIR)),)
 $(C_SRC_ENV):
-	$(verbose) $(ERL) -eval "file:write_file(\"$(C_SRC_ENV)\", \
+	$(verbose) $(ERL) -eval "file:write_file(\"$(call core_native_path,$(C_SRC_ENV))\", \
 		io_lib:format( \
 			\"ERTS_INCLUDE_DIR ?= ~s/erts-~s/include/~n\" \
 			\"ERL_INTERFACE_INCLUDE_DIR ?= ~s~n\" \